MARTENSITIC HEAT-RESISTING STEEL HAVING EXCELLENT RESISTANCE TO HAZ SOFTENING AND PROCESS FOR PRODUCING THE STEEL

Abstract: A martensitic heat-resisting steel which contains on the mass basis 0.01-0.30 % of carbon, 0.02-0.80 % of silicon, 0.20-1.00 % of manganese, 5.00-18.00 % of chromium, 0.005-1.00 % of molybdenum, 0.20-3.50 % of tungsten, 0.02-1.00 % of vanadium, 0.01-0.50 % of niobium and 0.01-0.25 % of nitrogen, and further contains at least one element selected from the group consisting of 0.005-2.0 % of titanium, 0.005-2.0 % of zirconium 0.005-2.0 % of tantalum and 0.005-2.0 % of hafnium, and wherein the total content of titanium zirconium, tantalum and hafnium in the metallic component M of a carbide of M₂₃C₆ type is 5-65 %. The steel is produced by adding titanium, zirconium, tantalum and hafnium to a molten steel having the above-specified chemical composition during the period from 10 minutes before the completion of refining to the completion of refining, then casting and working the refined steel, subjecting the worked steel to solution heat-treatment, suspending the cooling step at 950 to 1,000°C, and holding the steel thus treated at that temperature for 5-60 minutes. The obtained steel has an excellent resistance to HAZ softening and exhibits a high creep strength at a temperature as high as 550°C or above.

Description: FIELD OF THE INVENTION The present invention relates to a martensitic heat-resisting steel, and more in detail, to a martensitic heat-resisting steel excellent in HAZ-softening resistance and used in a high temperature and high pressure environment. BACKGROUND OF THE INVENTION Boilers of thermal power plants have been operated under conditions of markedly high temperature and high pressure in recent years. Part of them are planned to be operated at 566°C and 316 bar. It is estimated that some of them will operate at 649°C and 352 bar in the future. Accordingly, materials for such boilers will be used under extremely harsh conditions. When the operation temperature exceeds 550°C, materials used in the boilers will be changed, for example, from ferritic 2.1/4% Cr-1% Mo steel to an austenitic steel of high grade such as 18-8 stainless steel in view of oxidation resistance and high temperature strength. Thus, materials of very high grade and high cost are currently used. Steel materials having an intermediate grade between 2.1/4% Cr-1% Mo steel and austenitic stainless steel have been searched for in the past several decades. Boiler tube steels containing an intermediate amount of Cr such as 9% Cr steel or 12% Cr steel have been developed on the basis of the demands described above. Some of the steels have attained a high temperature strength and a creep strength comparable to austenitic steels by precipitation strengthening or solid solution strengthening effected by adding a variety of alloying elements as base material components. The creep strength of heat-resisting steels is governed by solid solution strengthening when the steels have been aged for a short period of time and by precipitation strengthening when they have been aged over a long period of time. This is because solid solution strengthening elements dissolved in the steels are precipitated at first as stable carbides such as M 23 C 6 by aging in many cases. However, when the steels are aged for a still longer period of time, the precipitates are coalescence coarsened, and as a result the creep strength is lowered. Many studies have, therefore, been performed on maintaining the solid solution strengthening elements in a solution state in the steels over a long period of time without precipitation in order to maintain the high creep strength of the heat-resisting steels. For example, Japanese Patent Unexamined Publication (Kokai) Nos. 63-89644, 61-231139 and 62-297435 disclose ferritic heat-resisting steels which can achieve a creep strength far higher than a conventional Mo-added type ferritic heat-resisting steel by the use of W as a solid solution strengthening element. Many of these steels have a tempered martensite single phase as their structure, and are expected to become the next generation of materials for use in high temperature and high pressure environments due to their advantage as ferritic steels excellent in steam oxidation resistance and due to their high strength properties. On the other hand, ferritic heat-resisting materials utilize the high strength of a martensite structure containing a large amount of dislocations or its tempered structure formed by the supercooling phenomenon of phase transformation from an austenite single phase region to (ferrite + carbide precipitate) the phase to be produced as a result of cooling during heat treatment. Accordingly, when the structure is subjected to a heat cycle of being reheated to the austenite single region, for example, when the structure is subjected to weld heat affection, the dislocations of high density are relieved again, and the strength is sometimes locally decreased in the weld HAZ (heat-affected zone). Particularly among those portions which are reheated to a temperature of at least a ferrite-austenite transformation point, portions which has been heated to a temperature near the transformation point, for example, about from 900 to 1,000°C in the case of 9% Cr steel, and recooled in a short period of time are subjected to martensite transformation while austenite grains do not grow sufficiently to become a fine grain structure. In addition, M 23 C 6 type carbides which are a principal factor in improving the materials strength by precipitation strengthening do not redissolve, and mechanisms for inducing a decrease in the high temperature strength such as alteration of the constituent components of the carbides, or carbide coarsening, may compositely act on the portion to locally become a softened zone. The softening zone-forming phenomenon is termed "HAZ-softening" for convenience. DE-A-42 12 966 discloses a nitrogen alloyed martensitic heat resistant steel which comprises 14-18 %Cr, 0.5-3 %Mo, 0.5-3%W, 0.2-1 %V 0.3-2%Nb and 0.2-1.0%N which comprises nitrides of the type CrN with about 80 %Cr. DISCLOSURE OF THE INVENTION The present inventors have carried out detailed studies on the softening zone, and found that the decrease in strength is caused mainly by a change of the constituent elements in M 23 C 6 type carbides. As the result of further investigation, they discovered that when high strength martensitic heat-resisting steel is being subjected to the weld heat affection, Mo or W particularly essential to solid solution strengthening thereof is dissolved in the constituent element M of M 23 C 6 in a large amount and precipitates at grain boundaries of the fine grain structure, and that as a result, a Mo- or W-depleted zone is formed near the austenite grain boundaries, resulting in a local decrease in the creep strength. Accordingly, the decrease in the creep strength caused by weld heat affection is critically disadvantageous to heat-resisting materials. It is obvious that the prior art aiming at optimization of heat treatment and welding cannot solve the problems. In addition, it is evident that a countermeasure of completely austenitizing a welded portion again which had been recognized as the sole solution cannot be practiced when the process of construction and execution of works in power plant is taken into consideration. Accordingly, it is clear that manifestation of the "HAZ-softening" phenomenon is inevitable in a conventional heat-resisting martensitic or ferritic steel. An object of the present invention is to overcome the disadvantage of the conventional steel, namely to avoid the formation of a local softening zone in a weld HAZ caused by alteration and coarsening of M 23 C 6 type carbides. A further object of the present invention is to prevent Mo or W from being dissolved in M 23 C 6 in a large amount while the steel material is being subjected to weld heat affection To achieve the objects as mentioned above in the present invention, the composition and the precipitation size of M 23 C 6 type carbides in a weld HAZ are controlled. As the result of intensively investigating the "HAZ-softening" phenomenon to achieve the objects as mentioned above, the present inventors have discovered that Ti, Zr, Ta and Hf each have an extremely strong affinity with C in the component system of the steel according to the present invention, that carbides of these elements become precipitation nuclei of M 23 C 6 carbides to be precipitated in the tempered martensite structure of the steel according to the present invention, and these elements dissolve in solid solution state at the same time in the metal component M in the carbides, that when the solid solution amount in the metal component M is within a specific range, the creep rupture strength of the weld HAZ falls down to only an extremely small value within the deviation of the creep rupture strength of the base material compared with the rupture strength thereof, and that as a result, the weld HAZ does not exhibit the "HAZ-softening" phenomenon any more. The following process has been developed to realize the discovery. First, since the precipitates of Ti, Zr, Ta and Hf are each required to become fine and appropriate, that is, since all of the precipitates must become carbides and carbonitrides, these elements are each added to the molten steel in a state of a low oxygen concentration immediately before completion of refining. Second, since these precipitates of Ti, etc. are required to become precipitation nuclei of M 23 C 6 to be precipitated within the tempered martensite structure and to be dissolved in solid solution state in the resultant carbides in suitable amounts, the steel slab is processed as follows: the steel slab having been subjected to a solid solution heat treatment is subjected to cooling stop at a temperature of 950 to 1,000°C in the course of cooling; and the steel slab is held at the temperature for a predetermined period of time to sufficiently precipitate fine carbides of Ti, etc. As described above, when a steel material having a martensite structure in which fine carbides of Ti, etc. are precipitated is tempered, M 23 C 6 type carbides are precipitated while the carbides of Ti, etc. are utilized as the precipitation nuclei. M 23 C 6 carbides and the fine carbides of Ti, Zr, Ta and Hf are mutually dissolved in each other, and finally M 23 C 6 type carbides in which Ti, Zr, Ta and Hf are solid solubled in the prescribed range in the metal component M, are formed in the tempered martensite structure. As a result, the creep rupture strength of the weld HAZ is significantly improved. That is, the present invention provides a martensitic heat-resisting steel which comprises, in terms of % by mass, 0.01 to 0.30% of C, 0.02 to 0.80% of Si, 0.20 to 1.00% of Mn, 5.00 to 18.00% of Cr, 0.005 to 1.00% of Mo, 0.20 to 3.50% of W, 0.02 to 1.00% of V, 0.01 to 0.50% of Nb, 0.01 to 0.25% of N, up to 0.030% of P, up to 0.010% of S, up to 0.020% of O, at least one element selected from the group consisting of Ti, Zr, Ta and Hf in an amount of 0.005 to 2.0% for each of the elements, if necessary at least one element selected from the group consisting of Co, Ni and Cr in an amount of 0.2 to 5.0% for each of Co and Ni and 0.2 to 2.0% for Cu, and the balance Fe and unavoidable impurities, and which has in the tempered martensite structure precipitated M 23 C 6 type carbides, the value of (Ti% + Zr% + Ta% + Hf%) in the metal component M thereof being from 5 to 65%. The present invention provides a process for producing said heat-resisting steel comprising the steps of adding at least one element selected from the group consisting of Ti, Zr, Ta and Hf to a molten steel during the period from 10 minutes before completion of refining to completion thereof, subjecting the steel to temporary cooling stop at a temperature of 950 to 1,000°C in the course of cooling the steel after solution heat treatment, holding the steel at that temperature for 5 to 60 minutes, and tempering it. The invention is defined in claims 1 and 3. Preferred embodiments are defined in claims 2 and 4-6. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a butt groove shape of a welded joint. Fig. 2 is a view showing a procedure for sampling test pieces for analyzing precipitates in a weld HAZ. Fig. 3 is a diagram showing the relationship between the addition time of Ti, Zr, Ta and Hf, and the form and the average particle size of precipitates of Ti, Zr, Ta and Hf in the steel. Fig. 4 shows graphs each showing the relationship between a temporary cooling stop temperature after solution treatment and a holding time thereat, and the particle size of the precipitated carbides. Fig. 5 is a diagram showing the relationship between a temporary cooling stop temperature after solution treatment, and the form and the structure of the precipitates in a weld HAZ. Fig. 6 is a graph showing the relationship between a difference (D-CRS) between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld HAZ, and the value of M% (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in the weld HAZ. Fig. 7 is a graph showing the relationship between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and the value of Ti% + Zr% + Ta% + Hf% in the base steel. Fig. 8 is a graph showing the relationship between the value of M% (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in the weld HAZ and the toughness thereof. Fig. 9(a) and Fig. 9(b) are views showing a procedure for sampling a creep rupture strength test piece from a steel tube and a procedure therefor from a plate or sheet, respectively. Fig. 10(a) and Fig. 10(b) are views showing a procedure for sampling a creep rupture test piece from a weld zone of a steel tube and a procedure therefor from a weld zone of a plate or sheet, respectively. Fig. 11(a) and Fig. 11(b) are views showing a procedure for sampling a Charpy impact test piece from a weld zone of a steel tube and a procedure therefor from a weld zone of a plate or sheet, respectively. DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be explained. First, the reasons for restricting the contents of components in the molten steel in the present invention as mentioned above are described below. A content expressed in terms of % signifies a content in terms of % by mass. Though C is necessary for maintaining the strength of the steel, C in a content of less than 0.01% is insufficient for ensuring the strength of the steel. When the content of C exceeds 0.30%, the weld HAZ is markedly hardened, and as a result cold cracking is formed at the time of welding. Accordingly, the content range of C is defined to be from 0.01 to 0.30%. Si is important in ensuring the oxidation resistance of the steel, and it is also a necessary element as a deoxidizing agent. Si in a content of less than 0.02% is insufficient, and Si in a content exceeding 0.80% lowers the creep strength of the steel. Accordingly, the content range of Si is defined to be from 0.02 to 0.80%. Mn is a component necessary not only for deoxidization but also for maintaining the strength of the steel. Addition of Mn in a content of at least 0.20% is necessary for obtaining a sufficient effect. Mn in a content exceeding 1.00% may sometimes lower the creep strength of the steel. Accordingly, the content range of Mn is defined to be from 0.20 to 1.00%. Cr is an element essential to the oxidation resistance of the steel. Cr combines with C at the same time in forms of Cr 23 C 6 ·Cr 7 C 3 , etc. to form fine precipitates in the base steel matrix, and thus contributes to an increase in the creep strength of the steel. From the standpoint of oxidation resistance, the lower limit of the Cr content is defined to be 5.0%. The upper limit thereof is defined to be 18.0% from the standpoint of ensuring a high temperature strength of the steel and in view of the limit for achieving a martensite single phase. W is an element significantly enhancing the creep strength of the steel through solution hardening. W particularly increases the long term creep strength at high temperatures of at least 550°C. When W is added in a content exceeding 3.5%, it precipitates mainly at grain boundaries as intermetallic compounds in a large amount. As a result, the toughness and the creep strength of the base steel are markedly lowered. The upper limit of the W content is, therefore, defined to be 3.5%. Moreover, W in a content of less than 0.20% is insufficient for achieving the effect of solid solution strengthening. Accordingly, the lower limit of the W content is defined to be 0.20%. Mo also enhances the high temperature strength of the steel through solid solution strengthening. Mo in a content of less than 0.005% is insufficient for achieving the effect. Since MO 2 C type carbide is precipitated in a large amount or Mo 2 Fe type intermetallic compound is precipitated when the content of Mo exceeds 1.00%, simultaneous addition of Mo and W may considerably lower the toughness of the base steel. Accordingly, the upper limit of the Mo content is defined to be 1.00%. V is an element which significantly enhances the high temperature creep rupture strength of the steel when it is precipitated as precipitates or when it is dissolved in the matrix in the same manner as W. In the present invention, V in a content of less than 0.02% is insufficient for precipitation strengthening the steel with V precipitates, and on the other hand V in a content exceeding 1.00% forms clusters of V type carbides or carbonitrides which lower the toughness of the steel. Accordingly, the V content is defined to be from 0.02 to 1.00%. Nb precipitates as NX type carbides or carbonitrides to increase the high temperature strength of the steel and contribute to solid solution strengthening. When the Nb content is less than 0.01%, the addition effects are not noticeable. When the Nb content exceeds 0.50%, coarse precipitates are formed to lower the toughness. Accordingly, the addition content range of Nb is defined to be from 0.01 to 0.50%. N is dissolved in the matrix or precipitates as nitrides and carbonitrides. N contributes to solution hardening and precipitation hardening of the steel principally in the forms of VN, NbN or their carbonitrides. N in an addition content of less than 0.01% exhibits almost no contribution to strengthening of the steel. Moreover, the upper limit of the addition content thereof is defined to be 0.25% while the upper limit of the addition content thereof in molten steel in accordance with the Cr addition content of up to the maximum value of 18% is taken into consideration. The addition of Ti, Zr, Ta and Hf constitutes the foundation of the present invention. The addition of these elements and the process according to the present invention realizes prevention of the "HAZ-softening" in the steel of the invention. Ti, Zr, Ta and Hf have an extremely strong affinity with C in the component system of the steel of the invention, and dissolve in M of M 23 C 6 as constituent elements to raise the decomposition temperature thereof. Accordingly, these elements are effective in preventing M 23 C 6 from coarsening in the "HAZ-softening" zone. In addition, these elements prevent W and Mo from dissolving in M 23 C 6 , and, therefore, a zone depleted in W and Mo is not formed around the precipitates. These elements may be added singly or compositely in a mixture of at least two of them. These elements each in a content of at least 0.005% already show the effects. Since any one of these elements in a content of at least 2.0% forms coarse MX type carbides and deteriorates the toughness of the steel, the addition content range of each of them is defined to be from 0.005 to 2.0%. P, S and O are mixed into the steel of the invention as impurities. However, in view of displaying the effect of the invention, P and S lower the strength, and O precipitates as an oxide and lowers the toughness of the steel. Accordingly, the upper limits of P, S and O are defined to be 0.03, 0.01 and 0.02%, respectively. Though the fundamental components of the steel of the present invention are as described above, the steel of the invention may optionally contain one or at least two elements selected from the group consisting of Ni, Co and Cu. The steel of the invention may contain from 0.1 to 5.0% of Ni, from 0.1 to 5.0% of Co and from 0.1 to 2.0% of Cu. Ni, Co and Cu are all potent elements for stabilizing austenite structure. Particularly when large amounts of ferrite-stabilizing elements, namely Cr, W, Mo, Ti, Zr, Ta, Hf, Si, etc., are added, Ni, Co, Cu are necessary for obtaining complete martensite or its tempered structure, and these elements are useful. At the same time, Ni and Co are effective in improving the toughness and the strength of the steel, respectively, and Cu is effective in improving the strength and corrosion resistance thereof. A content of each of these elements of less than 0.1% is insufficient for achieving these effects. When Ni or Co are each added in a content exceeding 5.0% or when Cu is added in a content exceeding 2.0%, it is inevitable that coarse intermetallic compounds are precipitated in the case of adding Ni or Co, and that intermetallic compounds are formed in a film form along grain boundaries in the case of adding Cu. These elements are, therefore, added in the content ranges as mentioned above. However, since the above-mentioned effects of adding these elements become significant when they are each added in a content of at least 0.2%, the lower limit of the addition content of each of these elements is desirably 0.2%. To obtain appropriate effects of adding Ti, Zr, Ta and Hf, the value of (Ti% + Zr% + Ta% + Hf%) in the metal component M of M 23 C 6 type carbides existing in the weld HAZ is required to be from 5 to 65%. To satisfy the requirement through precipitation of these elements in the form of appropriate carbides in the steel, the steel production process is carried out as follows: Ti, Zr, Ta and Hf are added during the period from 10 minutes before completion of refining to completion of refining; cooling the steel subsequent to solution treatment which is usually performed by holding the steel at temperature of 900 to 1,350°C for a period of 10 minutes to 24 hours is temporarily stopped at a temperature from 950 to 1,000°C, and the steel is held at the temperature for a period of 5 to 60 minutes to control the precipitated forms of the carbides. The precipitates thus obtained can be utilized as precipitation nuclei of M 23 C 6 mainly containing Cr to be precipitated subsequent tempering, which is usually carried out by holding the steel at a temperature of 300 to 850°C for a period of 10 minutes to 24 hours. The effects of adding Ti, Zr, Ta and Hf can be appropriately manifested and the object of the invention can be achieved only by applying the process as mentioned above. The intended effects of the present invention cannot be achieved even if a steel is produced merely by a conventional process using materials having the adjusted chemical composition of the invention. That is, the value of (Ti% + Zr% + Ta% + Hf%) in the metal component M of M 23 C 6 type carbides existing in the weld HAZ cannot be controlled to be from 5 to 65%. The production process and the composition range of carbides as mentioned above have been determined by experiments as described below. A molten steel having a chemical composition as claimed in the claims of the present invention except for Ti, Zr, Ta and Hf was prepared by using a VIM (vacuum induction heating furnace) or EF (electric furnace), and selecting and using an AOD (argon-oxygen blowing decarbonization refining unit), a VOD(vacuum exhausting oxygen blowing decarbonization unit) or LF (molten steel ladle refining unit), and cast into a slab having a cross section of 210 × 1,600 mm by a contnuous casting unit. The influence of the addition time of Ti, Zr, Ta and Hf on the composition and the shape of precipitates after casting was investigated by adding these elements at any of the following times: at the start of melting, during melting or 5 minutes before completion of melting in a VIM or EF; at the start of refining process or 10 minutes before completion thereof in an AOD, a VOD or LF. Each of the slabs thus cast was sectioned so that each piece thus obtained had a length of 2 to 5 m and plates each having a thickness of 25.4 mm were formed. The plates were then solution treated under the conditions of the maximum heating temperature of 1,100°C and a holding time of 1 hour. In the course of cooling the plates, cooling was stopped at a temperature of 1,050, 1,000, 950, 900, 850 or 800°C, and the plates were held at the temperature for up to 24 hours in the furnace and air cooled. Precipitates in the plates were then subjected to residue-extraction analysis, and the precipitation forms of carbides in the plates were examined using a transmission electron microscope with a micro X-ray analysis apparatus. Furthermore, each of the steel plates thus obtained was tempered at 780°C for 1 hour, subjected to edge preparation for V-shaped butt welding with a groove angle of 45 degrees, and used for welding experiments. The experiments were carried out by using TIG arc welding under a selected heat input condition of 15,000 J/cm which is a general heat input for martensitic heat-resisting materials. The welded joint samples thus obtained were subjected to post weld heat treatment at 740°C for 6 hours, and thin film disc samples for transmission electron microscopic observation and block test pieces for extraction-residue analysis were sampled from the HAZ portions of the samples by procedures as shown in Fig. 2. Fig. 3 shows the relationship between the addition time of Ti, Zr, Ta and Hf, and the form and the average particle size of precipitates of Ti, Zr, Ta and Hf in the steel. In order that the precipitates of Ti, Zr, Ta and Hf may become precipitation nuclei of M 23 C 6 and solid soluble in the constituent metal element M of M 23 C 6 , these elements must exist as fine carbides (including carbonitrides) in advance in the molten metal. It is understood that to satisfy the requirement, these elements are required to be added to molten steel having a low oxygen concentration, that is, these elements must be added to molten steel during the period from 10 minutes before completion of refining in a VOD or LF to at the time of completion thereof. The average particle size of carbides at this time, namely carbides in steels produced by casting the molten steels or ingot-making thereof has been found to be approximately 0.15 µm by electron microscopic observation of the carbides. The particle size of the precipitates should desirably be made as small as possible in view of the precipitation strengthening mechanism. When the cast slab, etc. thus obtained is subjected to hot working, solution treatment, cooling (air cooling) to room temperature, working and tempering, carbides of Ti, etc. precipitated in the tempered worked product become fine. However, the amount of the carbides thus formed is only about half as much as that of carbides of Ti, etc. having been precipitated in the slab at the time of its production. In addition, the carbides are precipitated as MC type carbides other than M 23 C 6 type carbides. As a result, the "HAZ-softening" phenomenon takes place in the tempered worked product. As a result of investigating the relationship between cooling conditions after solution treatment and precipitated carbides using cast slabs (having chemical components the contents of which are in the range as claimed in the claims of the present invention) produced by the process of EF-LF-CC, the present inventors have clarified that the cooling stop temperature subsequent to solution treatment and the holding time at the temperature have an extremely important relationship with the particle size of the precipitated carbides. That is, it has been confirmed that the average particle size of carbides precipitated in the steels becomes smallest when the cooling stop temperature and the holding temperature are from 950 to 1,000°C and that most of the carbides having been precipitated in the cast slabs are reprecipitated when the slabs are held for a holding time of 5 to 60 minutes. Taking the research results as described above into consideration, the present inventors carried out the following experiments: cast slabs, etc. used in Fig. 3 were worked, solution treated, subjected to air cooling which was stopped at a variety of temperatures including 950°C and 1,000°C, held at respective cooling stop temperatures for 30 minutes, and further air cooled to room temperature; the samples thus obtained were tempered at 780°C for 1 hour; the samples were welded, and heat treated; and the relationship between the forms and compositions of the principal precipitates in the weld HAZ, and the cooling stop temperature was investigated. The results thus obtained are shown in Fig. 5. It is seen from Fig. 5 that the carbides which take the finest precipitation forms prior to tempering (carbides in the steels which have been subjected to cooling stop at a temperature of 950°C or 1,000°C) become precipitation nuclei of M23C6, that the carbides and M 23 C 6 precipitated during tempering mutually dissolve in each other to finally form M 23 C 6 type carbides, and that Ti, Zr, Ta and Hf are dissolved in the constituent metal element M in a proportion of 5 to 65% in total. Furthermore, it has been found that the weld HAZ as mentioned above has a very high creep rupture strength at high temperature. Fig. 6 shows the relationship between a difference (D-CRS (MPa)) between the creep rupture strength of the base steels at 600°C for 100,000 hours and that of the weld HAZ, and the value of M% (Ti% + Zr% + Ta% + Hf%) in M 23 C 6 type carbides in the weld HAZ. When M% is from 5 to 65, the creep rupture strength of the weld HAZ decreases by only up to 7 MPa compared with that of the base steels. Since the difference is within the deviation of the-creep rupture strength data of the base steels (10 MPa), it is understood that the weld HAZ no longer exhibits HAZ-softening. It can be concluded that the experimental results are brought about for the following reasons: M 23 C 6 type carbides containing from 5 to 65% of Ti, Zr, Ta and Hf in the constituent element M have a high decomposition temperature compared with ordinary M 23 C 6 type carbides containing mainly Cr in M, and are not subject to be coalescence coarsening even after weld heat affection; moreover, W and Mo are extremely difficult to dissolve in place of or in addition to Ti, Zr, Ta and Hf due to their chemical affinities and phase diagrams. In addition, each of the elements Ti, Zr, Ta and Hf influences the creep strength of the base steels. Fig. 7 shows the relationship between the creep rupture strength of the base steels at 600°C for 100,000 hours and the value of Ti% + Zr% + Ta% + Hf% in the base steels. It is evident from Fig. 7 that excessive addition of Ti, Zr, Ta and Hf causes precipitate coarsening, and that as a result the creep rupture strength of the base steels themselves decreases. When the total amount of Ti% + Zr% + Ta% + Hf% in the base steels is up to 8%, the creep rupture strength thereof becomes at least the evaluation standard value of 130 MPa and causes no problem. When the upper limit of the total amount of Ti, etc. is 8%, the content of each of the elements Ti, Zr, Ta and Hf does not exceed 2%, and is within the content range as claimed in the present invention. Next, the toughness of the weld HAZ of the steel according to the present invention will be explained. Fig. 8 shows the relationship between the value of Ti% + Zr% + Ta% + Hf%, namely M% in M 23 C 6 in the weld HAZ and the toughness of the weld HAZ. It is understood from Fig. 8 that when M% exceeds 65%, the precipitates are coarsened and the toughness of the weld HAZ decreases, and that the toughness falls below the evaluation standard value of 50 J. In addition, in the toughness test, a 2 mm V-notched Charpy impact test piece 11 in accordance with JIS No.4 was cut out of a portion containing a weld zone and located in the direction normal to the weld line as shown in Fig. 11(a) and Fig. 11(b). The notch was formed at a weld bond 9, which was represented by the hardest portion and shown. The evaluation standard value was defined to be 50 J at 0°C while the construction conditions of heat-resisting materials were taken into consideration. The reference numeral 10 designates a weld HAZ. As described above, the steel of the invention having a value of 5 to 65% as M% is also excellent in toughness. The process of the present invention has been determined as claimed in the claims on the basis of the results as mentioned above. When a steel having a chemical composition according to the present invention is produced without applying the process of the present invention, it is impossible to obtain in the weld HAZ M 23 C 6 carbides having the same composition as mentioned in the present invention. There is no limitation on the method for melting the steel of the invention. The process can be determined in a satisfactory way taking into consideration converters, induction heating furnaces, arc melting furnaces, electric furnaces, etc., and chemical components and the cost of the steel. The unit used in the refining step is required to be equipped with a hopper which can add Ti, Zr, Ta and Hf and which is capable of controlling the oxygen concentration in the molten steel at a sufficiently low one so that at least 90% of these added elements can be precipitated as carbides. Accordingly, an LF equipped with an Ar-blowing unit, an arc heating unit or plasma heating unit, or a vacuum degassing unit is advantageously used. The use of them will enhance the effects of the invention. Furthermore, in the subsequent rolling step or tube milling step in the case of producing a steel tube, solution treatment is essential for the purpose of uniformly redissolving the precipitates. There is required an installation capable of stopping the cooling of the steel at a given temperature in the course of cooling after solution treatment, and holding at that temperature, and a furnace which can heat the steel up to 1,350°C is required. There can be applied production steps other than those mentioned above, concretely, all production steps recognized as necessary or useful for producing a steel or a steel product by the present invention, for example, forging, rolling, heat treatment, tubing, welding, sectioning, inspection, and the like. Their application by no means impairs the effects of the present invention. Particularly in the production of steel tubes, the following production processes of steel tubes can be applied to the present invention under the condition that the processes comprise the production steps of the present invention without fail: a process for producing a seamless pipe or tube comprising the steps of working a steel to form a round or square billet, and hot extruding or seamless rolling the billet in various ways; a process for producing an electric welded tube comprising the steps of hot rolling and cold rolling a steel sheet, and resistance welding the rolled sheet; and a process for producing a welded steel tube comprising carrying out TIG arc welding, MIG welding, SAW, LASER welding and EB welding singly or in combination. Furthermore, there can be additionally practiced after carrying out each of the processes as mentioned above any of hot or warm SR (squeeze rolling), sizing rolling, and a variety of levelling steps. The applicable size of the steel of the invention can thus be expanded. The steel of the present invention may further be provided in the form of a plate or sheet. The plate or sheet having been subjected to necessary heat treatment may be used as a heat-resisting material with various shapes, and exerts no adverse effects in the present invention. Still furthermore, there may be applied to the process of the present invention powder metallurgy processes such as HIP (hot isostatic press sintering unit), CIP (cold isostatic pressing unit) and sintering. Products having a variety of shapes can be obtained by subjecting the resultant compacted products to indispensable heat treatment. The steel tubes, steel plates and heat-resisting steel materials of various shapes thus obtained may be subjected to respective heat treatments depending on the object and application. These heat treatments are important to obtain sufficient effects of the present invention. Usually, the products of the invention are obtained through the steps of normalizing (solution treatment) and tempering. The products may further be retempered and/or normalized, and the step is useful. In addition, cooling stop at a temperature of the steel and holding it at the temperature after solution treatment are essential to the process of the invention. When the steel of the invention has a relatively high content of nitrogen or carbon, when the steel contains austenite-stabilizing elements such as Co, Ni and Cu in a large amount or when the steel has a low Cr equivalent, the so-called sub-zero treatment wherein the steel is cooled to up to 0°C may be applied thereto to avoid retained austenite phase formation. The treatment is effective in sufficiently manifesting the mechanical properties of the steel of the invention. Each of the steps mentioned above may also be applied at least twice so long as the repetition of the steps is necessary for sufficiently manifesting the material properties, and the repetition exerts no adverse effects in the present invention. The steps as mentioned above may suitably be selected and applied to the process for producing the steel of the present invention. EXAMPLES A molten steel having components except for Ti, Zr, Ta and Hf as shown in some of Table 1-1 to Table 25-3 was prepared in an amount of 300 ton, 120 ton or 60 ton by the blast furnace pig iron-converter blowing process, using a VIM or EF, and refined in an LF unit having an arc reheating unit and capable of blowing Ar. At least one of the elements Ti, Zr, Ta and Hf was added to the molten steel in amounts as shown in the table 10 minutes before completion of refining, and the molten steel was continuously cast to obtain a slab. The slab thus obtained was hot rolled to give a plate 50 mm thick and a sheet 12 mm thick, or the slab was worked to give a round billet which was hot extruded to give a tube having an outer diameter of 74 mm and a thickness of 10 mm or which was seamless rolled to give a pipe having an outer diameter of 380 mm and a thickness of 50 mm. The sheet was formed, and electric welded to give an electric welded steel tube having an outer diameter of 280 mm and a thickness of 12 mm. All the plates, sheets and tubes thus obtained were solution treated at 1,100°C for 1 hour, subjected to a temporary cooling stop at a temperature of 950 to 1,000°C and held at that temperature for 5 to 60 minutes in the furnace, air cooled, and tempered at 780°C for 1 hour. The plates and sheets thus obtained were subjected to edge preparation exactly in the same manner as shown in Fig. 1. A groove which was the same as in Fig. 1 was formed in each of the tubes thus obtained at the edge in the circumferential direction. The worked plates and sheets were welded and the worked tubes were subjected to circular joint welding, by TIG arc welding or SAW welding. All the welded portions were locally subjected to softening annealing (PWHT) by heating them at 740°C for 6 hours. The creep characteristics of the base steels were obtained as follows: a creep test piece 5 having a diameter of 6 mm was cut out of a portion other than a weld zone and a weld HAZ in a steel tube 1 in the direction parallel to the tube axis direction 2 as shown in Fig. 9(a), or a creep test piece 5 of the same size was cut out of the same portion as mentioned above in a plate 3 in the direction parallel to the rolling direction 4 as shown in Fig. 9(b); a creep rupture strength was measured at 600°C on the test piece, and the data thus obtained were linearly extrapolated to obtain a creep rupture strength for 100,000 hours. The creep characteristics of a weld zone was obtained as follows: a creep rupture test piece 8 having a diameter of 6 mm was cut out of each of the welded tubes or plates in a direction 7 normal to a weld line 6 as shown in Fig. 10(a) or Fig. 10(b); the results of measuring creep rupture strength at 600°C were linearly extrapolated to 100,000 hours. The creep characteristics thus obtained were compared with those of the base steels and evaluated. For convenience of description in the present invention, a "creep rupture strength" (HAZCRS (MPa)) signifies a creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation. A difference between the creep rupture strength of a base steel and that of a weld HAZ (D-CRS (MPa)) was used as an index of the "HAZ-softening" resistance of a weld zone. Although the value of D-CRS is somewhat influenced by the method of sampling a creep rupture test piece in the rolling direction of a sample, it has been empirically found by a preliminary experiment that the influence is within 5 MPa. Accordingly, a D-CRS value of up to 10 MPa signifies that the HAZ-softening resistance of the steel material is extremely good. Test pieces for precipitates of a HAZ portion were sampled by the procedure as shown in Fig. 2, and subjected to extraction-residue analysis by acid dissolution to identify M 23 C 6 , followed by determining the composition in M by a scanning type micro X-ray analysis apparatus. Ti% + Zr% + Ta% + Hf% thus obtained were represented by M%, and the precipitates were evaluated. The standard reference based on the experimental results is defined to be from 5 to 65%. The values of D-CRS, HAZCRS and M% were shown in Table 1-3, Table 2-3 to Table 25-3 in the form of numerical data together with chemical components. It is evident from the tables that the steels of the present invention No. 1 to No. 381 exhibited the maximum value of D-CRS of 7 MPa, the maximum value of HAZCRS of 180 MPa and the minimum value of HAZCRS of 130 MPa. Accordingly, the HAZ-softening resistance of the steels of the invention was extremely good. For comparison, steels which did not correspond to any of the claims of the present invention were evaluated in the same manner. The chemical components and the values of D-CRS, HAZCRS and M% among the evaluation results are shown in Table 26-1 to Table 26-2. Experimental results about comparative steels in Table 26-1 to Table 26-2 are as described below. Though No. 721 steel and No. 722 steel had the same chemical components as the steel of the invention, Ti and Zr were added at the time of melting. As a result, the value of M% became up to 5%, and the HAZ-softening resistance deteriorated. In No. 723 steel and No. 724 steel, Ti, Zr, Ta and Hf were not sufficiently added. As a result, M% became low, and the HAZ-softening resistance deteriorated. No. 725 steel, No. 726 steel, No. 727 steel and No. 728 steel were instances wherein a number of coarse MX type carbides were precipitated, composition control of M 23 C 6 in the weld HAZ could not be achieved, and as a result the HAZ-softening resistance deteriorated, due to excessive addition of Ti in the case of No. 725 steel, excessive addition of Zr in the case of No. 726 steel, excessive addition of Ta in the case of No. 727 steel and excessive addition of Hf in the case of No. 728 steel. Since a temporary cooling stop was not practiced after solution treatment in the production of No. 729 steel, composition control of M 23 C 6 therein could not be achieved, and the HAZ-softening resistance deteriorated. In the production of No. 730 steel, since the holding time was 240 minutes which was overly long after solution treatment and the temporary cooling stop, the precipitates therein were coarsened, and composition control of M 23 C 6 could not be achieved. As a result, the HAZ-softening resistance deteriorated. STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 1 0.26 0.24 0.46 16.73 0.753 1.88 0.69 0.33 0.17 2 0.24 0.63 0.68 16.40 0.126 0.92 0.44 0.44 0.03 3 0.05 0.30 0.69 15.19 0.120 2.65 0.68 0.40 0.21 4 0.06 0.29 0.79 11.23 0.082 1.57 0.26 0.11 0.20 5 0.10 0.48 0.84 8.84 0.841 2.08 0.50 0.49 0.08 6 0.25 0.74 0.70 12.33 0.250 0.38 0.26 0.48 0.05 7 0.18 0.16 0.25 13.11 0.128 2.48 0.35 0.47 0.07 8 0.14 0.56 0.55 15.41 0.301 2.87 0.60 0.15 0.10 9 0.06 0.24 0.67 17.20 0.625 2.72 0.87 0.41 0.10 10 0.20 0.27 0.47 9.83 0.427 1.44 0.50 0.44 0.15 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 1 1.790 - - - - - - 2 1.816 - - - - - - 3 0.952 - - - - - - 4 0.843 - - - - - - 5 1.168 - - - - - - 6 1.617 - - - - - - 7 - 1.597 - - - - - 8 - 1.940 - - - - - 9 - 0.310 - - - - - 10 - 1.352 - - - - - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 1 0.0259 0.002 0.012 2 170 19 2 0.0013 0.002 0.003 2 135 26 3 0.0239 0.005 0.003 3 164 18 4 0.0151 0.004 0.018 4 133 15 5 0.0287 0.003 0.007 0 172 19 6 0.0155 0.008 0.015 1 158 24 7 0.0003 0.002 0.019 2 168 20 8 0.0229 0.003 0.006 1- 180 20 9 0.0190 0.003 0.012 1 171 16 10 0.0280 0.004 0.014 2 171 20 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 11 0.22 0.49 0.64 17.23 0.050 3.46 0.30 0.41 0.21 12 0.22 0.41 0.63 17.66 0.814 3.30 0.13 0.48 0.24 13 0.15 0.28 0.32 15.59 0.078 2.05 0.79 0.07 0.09 14 0.10 0.75 0.78 8.84 0.157 0.82 0.17 0.09 0.19 15 0.17 0.52 0.67 14.68 0.395 2.36 0.55 0.47 0.15 16 0.18 0.26 0.26 5.12 0.130 1.20 0.31 0.37 0.04 17 0.07 0.21 0.22 10.58 0.199 1.75 0.27 0.46 0.19 18 0.22 0.64 0.42 9.12 0.924 3.43 0.74 0.17 0.19 19 0.17 0.64 0.73 11.97 0.665 0.80 0.11 0.15 0.13 20 0.15 0.10 0.63 16.90 0.246 3.19 0.18 0.32 0.09 21 0.25 0.03 0.36 15.00 0.487 1.78 0.76 0.35 0.15 22 0.15 0.32 0.21 17.52 0.755 2.72 0.26 0.18 0.02 23 0.07 0.46 0.84 15.56 0.858 0.42 0.45 0.44 0.04 24 0.13 0.31 0.93 7.19 0.653 2.65 0.21 0.33 0.15 25 0.13 0.53 0.34 16.17 0.961 0.58 0.34 0.24 0.09 26 0.15 0.57 0.92 14.13 0.114 0.25 0.18 0.35 0.16 27 0.02 0.74 0.98 12.43 0.972 1.21 0.10 0.35 0.22 28 0.13 0.50 0.76 8.64 0.356 2.86 0.41 0.38 0.22 29 0.12 0.51 0.94 7.18 0.102 1.35 0.44 0.36 0.25 30 0.10 0.24 0.59 12.46 0.044 2.76 0.54 0.23 0.02 31 0.03 0.73 0.37 15.70 0.017 1.57 0.54 0.13 0.09 32 0.28 0.31 0.95 8.42 0.864 2.23 0.29 0.25 0.19 33 0.24 0.40 0.20 7.98 0.920 2.52 0.60 0.24 0.15 34 0.14 0.09 0.79 5.65 0.518 1.92 0.34 0.04 0.18 35 0.23 0.43 1.00 12.41 0.496 3.17 0.80 0.04 0.12 36 0.17 0.50 0.68 13.01 0.682 2.41 0.85 0.17 0.17 37 0.05 0.57 0.50 11.87 0.915 2.43 0.81 0.36 0.16 38 0.27 0.13 0.34 13.42 0.051 2.69 0.55 0.02 0.06 39 0.05 0.21 0.87 8.96 0.896 2.65 0.86 0.06 0.07 40 0.21 0.29 0.75 9.27 0.298 3.37 0.10 0.16 0.04 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 11 - 1.738 - - - - - 12 - 1.155 - - - - - 13 0.139 1.257 - - - - - 14 1.612 1.716 - - - - - 15 1.252 0.233 - - - - - 16 1.732 0.455 - - - - - 17 1.697 0.052 - - - - - 18 0.825 1.705 - - - - - 19 - - 0.095 - - - - 20 - - 0.340 - - - - 21 - - 0.989 - - - - 22 - - 0.779 - - - - 23 - - 1.339 - - - - 24 - - 0.354 - - - - 25 0.981 - 0.498 - - - - 26 1.649 - 1.420 - - - - 27 0.561 - 1.818 - - - - 28 1.351 - 1.373 - - - - 29 1.702 - 1.729 - - - - 30 1.288 - 1.569 - - - - 31 - 0.689 0.535 - - - - 32 - 1.635 1.354 - - - - 33 - 0.709 0.668 - - - - 34 - 1.582 1.156 - - - - 35 - 1.931 0.482 - - - - 36 - 1.429 0.321 - - - - 37 1.355 1.736 1.335 - - - - 38 1.996 1.543 0.220 - - - - 39 0.922 0.512 0.631 - - - - 40 1.786 1.310 0.238 - - - - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 11 0.0156 0.009 0.009 1 156 25 12 0.0214 0.008 0.014 5 154 16 13 0.0106 0.008 0.015 5 143 22 14 0.0232 0.003 0.019 4 175 34 15 0.0246 0.001 0.013 1 179 18 16 0.0248 0.005 0.004 2 156 31 17 0.0037 0.004 0.016 5 135 20 18 0.0163 0.001 0.010 5 144 26 19 0.0278 0.005 0.020 2 135 8 20 0.0183 0.003 0.004 5 136 8 21 0.0129 0.009 0.007 6 150 14 22 0.0218 0.007 0.007 4 154 12 23 0.0247 0.010 0.001 4 177 20 24 0.0023 0.002 0.014 2 170 10 25 0.0090 0.004 0.006 0 162 17 26 0.0251 0.007 0.010 4 155 37 27 0.0161 0.004 0.015 3 152 26 28 0.0067 0.006 0.007 6 131 35 29 0.0219 0.009 0.013 0 145 38 30 0.0264 0.001 0.009 7 146 30 31 0.0163 0.004 0.012 6 162 17 32 0.0160 0.003 0.019 2 146 28 33 0.0207 0.009 0.008 2 175 24 34 0.0255 0.008 0.014 3 178 26 35 0.0107 0.007 0.004 0 131 27 36 0.0157 0.005 0.004 2 164 21 37 0.0061 0.009 0.012 4 177 41 38 0.0221 0.008 0.014 2 150 34 39 0.0284 0.002 0.008 1 135 29 40 0.0056 0.003 0.019 5 159 32 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 41 0.27 0.25 0.24 12.41 0.100 1.06 0.10 0.22 0.03 42 0.05 0.35 0.43 16.05 0.123 1.77 0.19 0.18 0.01 43 0.06 0.46 0.38 11.75 0.713 1.63 0.70 0.44 0.07 44 0.26 0.45 0.74 10.09 0.699 1.78 0.50 0.19 0.15 45 0.18 0.20 0.21 15.83 0.436 1.69 0.40 0.08 0.12 46 0.05 0.36 0.65 13.54 0.736 2.41 0.24 0.26 0.15 47 0.26 0.40 0.31 7.68 0.945 1.81 0.84 0.20 0.10 48 0.04 0.60 0.69 15.73 0.411 0.98 0.58 0.27 0.17 49 0.21 0.05 0.43 9.45 0.950 1.03 0.26 0.41 0.19 50 0.15 0.17 0.21 12.60 0.411 3.05 0.23 0.30 0.25 51 0.09 0.45 0.71 16.81 0.629 3.25 0.81 0.08 0.06 52 0.13 0.37 0.58 13.24 0.932 1.02 0.36 0.43 0.08 53 0.09 0.19 0.50 6.30 0.161 2.45 0.68 0.02 0.24 54 0.19 0.17 0.72 13.28 0.645 0.39 0.15 0.01 0.17 55 0.26 0.59 0.34 6.17 0.724 0.89 0.07 0.08 0.06 56 0.23 0.12 0.41 8.81 0.740 1.79 0.78 0.13 0.23 57 0.22 0.21 0.39 12.55 0.029 2.54 0.64 0.10 0.16 58 0.17 0.74 0.97 15.27 0.420 0.94 0.48 0.15 0.17 59 0.18 0.79 0.41 8.33 0.251 1.40 0.61 0.19 0.22 60 0.20 0.64 0.57 9.10 0.855 3.36 0.89 0.39 0.04 61 0.19 0.52 0.93 8.94 0.576 1.37 0.17 0.18 0.06 62 0.09 0.72 0.55 5.73 0.246 1.46 0.74 0.22 0.12 63 0.01 0.32 0.91 10.33 0.696 3.09 0.96 0.42 0.07 64 0.04 0.37 0.28 7.70 0.776 2.45 0.69 0.22 0.10 65 0.14 0.73 0.52 8.57 0.808 2.26 0.24 0.26 0.06 66 0.11 0.50 0.29 10.86 0.136 1.99 0.94 0.23 0.03 67 0.04 0.33 0.68 5.87 0.583 2.73 0.64 0.04 0.20 68 0.19 0.49 0.74 17.63 0.505 0.69 0.67 0.34 0.18 69 0.07 0.06 0.75 17.85 0.223 1.86 0.86 0.08 0.05 70 0.20 0.46 0.56 17.30 0.563 2.43 0.56 0.16 0.24 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 41 1.270 0.627 0.732 - - - - 42 1.055 0.131 0.780 - - - - 43 - - - 1.282 - - - 44 - - - 1.087 - - - 45 - - - 1.833 - - - 46 - - - 1.168 - - - 47 - - - 1.763 - - - 48 - - - 0.323 - - - 49 0.239 - - 0.471 - - - 50 0.589 - - 0.930 - - - 51 0.276 - - 0.342 - - - 52 1.979 - - 1.398 - - - 53 0.346 - - 1.758 - - - 54 0.098 - - 0.098 - - - 55 - 1.453 - 1.079 - - - 56 - 1.997 - 0.375 - - - 57 - 1.774 - 0.651 - - - 58 - 0.499 - 0.599 - - - 59 - 1.816 - 1.869 - - - 60 - 1.395 - 1.144 - - - 61 - - 1.682 1.102 - - - 62 - - 1.723 0.420 - - - 63 - - 1.419 1.755 - - - 64 - - 1.434 0.781 - - - 65 - - 0.457 0.180 - - - 66 - - 1.131 1.596 - - - 67 - 1.565 0.174 0.751 - - - 68 - 0.516 1.211 0.262 - - - 69 - 1.779 1.935 1.829 - - - 70 - 0.041 1.021 0.130 - - - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 41 0.0084 0.008 0.005 4 176 26 42 0.0168 0.003 0.002 2 163 23 43 0.0111 0.010 0.006 4 173 24 44 0.0161 0.002 0.006 1 133 19 45 0.0272 0.003 0.006 1 172 23 46 0.0091 0.002 0.005 0 142 22 47 0.0023 0.010 0.008 7 170 27 48 0.0016 0.007 0.003 1 160 10 49 0.0170 0.003 0.006 6 140 15 50 0.0142 0.003 0.004 4 136 17 51 0.0175 0.003 0.003 0 177 15 52 0.0076 0.005 0.011 0 166 35 53 0.0093 0.007 0.004 0 179 25 54 0.0026 0.004 0.009 2 171 7 55 0.0275 0.007 0.012 1 168 26 56 0.0193 0.003 0.011 3 149 29 57 0.0179 0.002 0.002 1 141 26 58 0.0034 0.003 0.020 2 171 16 59 0.0158 0.005 0.005 3 169 33 60 0.0205 0.002 0.001 6 160 32 61 0.0272 0.005 0.016 7 174 31 62 0.0167 0.005 0.017 4 162 28 63 0.0132 0.005 0.020 6 178 34 64 0.0122 0.002 0.003 6 149 31 65 0.0088 0.009 0.019 2 178 15 66 0.0128 0.002 0.020 7 168 30 67 0.0196 0.006 0.019 6 147 25 68 0.0090 0.003 0.005 5 142 26 69 0.0065 0.008 0.003 6 130 52 70 0.0216 0.002 0.009 1 141 23 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 71 0.12 0.04 0.47 14.15 0.389 1.88 0.59 0.25 0.25 72 0.06 0.58 0.71 12.41 0.506 1.27 0.79 0.02 0.02 73 0.26 0.03 0.80 16.86 0.283 1.78 0.03 0.14 0.13 74 0.10 0.21 0.56 12.06 0.531 2.80 0.59 0.03 0.05 75 0.25 0.60 0.29 9.07 0.105 0.55 0.35 0.34 0.22 76 0.09 0.29 0.25 12.17 0.327 2.70 0.62 0.26 0.24 77 0.29 0.70 0.30 12.77 0.044 0.48 0.26 0.45 0.08 78 0.08 0.55 0.72 15.14 0.576 1.57 0.57 0.08 0.05 79 0.29 0.10 0.58 10.74 0.275 0.50 0.91 0.31 0.24 80 0.28 0.77 0.53 16.79 0.957 1.65 0.13 0.31 0.12 81 0.30 0.10 0.45 11.82 0.476 1.20 0.04 0.01 0.13 82 0.15 0.69 0.62 6.58 0.663 0.27 0.47 0.31 0.12 83 0.08 0.46 0.89 11.99 0.845 1.58 0.77 0.38 0.05 84 0.19 0.45 0.74 12.88 0.373 1.33 0.29 0.41 0.24 85 0.28 0.15 0.43 7.25 0.577 0.62 0.35 0.30 0.04 86 0.16 0.22 0.65 12.39 0.792 2.21 0.29 0.22 0.15 87 0.08 0.12 0.84 13.14 0.855 2.25 0.93 0.34 0.15 88 0.12 0.13 0.90 13.94 0.605 1.85 0.15 0.32 0.02 89 0.25 0.11 0.66 12.44 0.861 0.44 0.72 0.10 0.18 90 0.12 0.34 0.43 13.31 0.983 2.49 0.05 0.31 0.12 91 0.26 0.27 0.44 7.63 0.289 2.44 0.40 0.16 0.17 92 0.21 0.19 0.59 13.01 0.619 3.10 0.66 0.29 0.04 93 0.04 0.74 0.33 14.16 0.316 0.61 0.16 0.37 0.05 94 0.01 0.63 0.33 15.50 0.214 2.69 0.70 0.34 0.05 95 0.21 0.11 0.47 8.31 0.632 0.49 0.16 0.09 0.11 96 0.16 0.61 0.60 16.59 0.924 1.80 0.34 0.06 0.08 97 0.25 0.07 0.21 5.61 0.424 1.06 0.59 0.14 0.03 98 0.28 0.30 0.36 5.85 0.466 2.76 0.28 0.03 0.05 99 0.21 0.80 0.53 8.72 0.893 1.38 0.69 0.38 0.21 100 0.27 0.64 0.97 11.99 0.537 2.95 0.20 0.37 0.12 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 71 - 0.959 0.136 0.829 - - - 72 - 0.207 1.931 0.576 - - - 73 1.690 - 0.124 1.077 - - - 74 1.669 - 1.346 1.982 - - - 75 1.132 - 0.292 0.976 - - - 76 0.733 - 1.636 0.741 - - - 77 1.144 - 1.047 0.932 - - - 78 1.047 - 0.175 1.207 - - - 79 1.103 1.777 - 0.273 - - - 80 1.962 1.910 - 1.785 - - - 81 1.337 1.417 - 0.404 - - - 82 0.868 0.962 - 0.806 - - - 83 1.253 0.256 - 0.676 - - - 84 1.139 0.928 - 1.675 - - - 85 0.236 0.671 0.100 0.467 - - - 86 1.171 0.156 0.291 0.738 - - - 87 0.654 0.051 0.247 1.156 - - - 88 1.329 1.029 0.669 0.395 - - - 89 0.872 1.763 0.209 0.132 - - - 90 1.956 1.935 1.548 1.028 - - - 91 1.262 - - - 0.63 - - 92 1.455 - - - 4.01 - - 93 1.218 - - - 3.88 - - 94 0.200 - - - 1.89 - - 95 0.077 - - - 2.04 - - 96 1.534 - - - 1.15 - - 97 - 1.537 - - 3.24 - - 98 - 0.293 - - 2.57 - - 99 - 0.537 - - 3.35 - - 100 - 0.912 - - 2.34 - - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M % 71 0.0049 0.001 0.012 7 150 23 72 0.0109 0.005 0.008 0 137 33 73 0.0202 0.006 0.013 6 179 35 74 0.0126 0.005 0.004 4 154 49 75 0.0286 0.003 0.008 4 138 30 76 0.0031 0.003 0.002 6 136 38 77 0.0058 0.010 0.002 1 149 29 78 0.0171 0.002 0.015 5 156 24 79 0.0022 0.002 0.017 7 160 35 80 0.0009 0.003 0.017 2 163 49 81 0.0081 0.004 0.019 2 142 30 82 0.0195 0.007 0.003 4 176 33 83 0.0295 0.008 0.002 3 142 28 84 0.0188 0.004 0.013 4 168 41 85 0.0119 0.007 0.006 3 131 22 86 0.0194 0.002 0.005 2 160 31 87 0.0208 0.002 0.017 3 157 30 88 0.0118 0.010 0.011 3 175 35 89 0.0024 0.005 0.001 2 167 37 90 0.0171 0.010 0.005 1 135 59 91 0.0213 0.008 0.018 5 157 17 92 0.0254 0.008 0.009 5 161 17 93 0.0089 0.008 0.004 4 175 16 94 0.0272 0.006 0.019 5 151 7 95 0.0007 0.007 0.002 7 167 8 96 0.0140 0.007 0.009 0 176 19 97 0.0172 0.002 0.015 2 155 24 98 0.0202 0.007 0.019 1 133 10 99 0.0036 0.007 0.009 2 161 12 100 0.0073 0.003 0.008 5 168 16 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 101 0.14 0.08 0.75 6.87 0.220 1.96 0.61 0.40 0.11 102 0.20 0.19 0.95 11.03 0.298 2.89 0.29 0.41 0.12 103 0.11 0.04 0.64 9.24 0.601 1.85 0.55 0.06 0.24 104 0.26 0.67 0.88 5.76 0.456 1.61 0.25 0.01 0.19 105 0.17 0.39 0.34 11.41 0.206 3.27 0.20 0.18 0.17 106 0.07 0.27 0.49 17.82 0.686 1.33 0.24 0.48 0.14 107 0.21 0.53 0.40 16.09 0.733 0.25 0.71 0.11 0.19 108 0.26 0.30 0.73 17.14 0.675 1.06 0.46 0.19 0.14 109 0.16 0.59 0.56 12.45 0.852 1.59 0.80 0.43 0.21 110 0.17 0.12 0.55 6.22 0.109 1.35 0.11 0.23 0.12 111 0.22 0.72 0.58 16.08 0.273 1.42 0.66 0.01 0.17 112 0.27 0.29 0.51 7.19 0.686 2.91 0.35 0.43 0.23 113 0.29 0.68 0.22 10.02 0.682 1.98 0.48 0.43 0.24 114 0.21 0.18 0.37 9.45 0.098 1.38 0.89 0.41 0.16 115 0.28 0.22 0.82 9.57 0.754 0.54 0.91 0.04 0.21 116 0.16 0.68 0.64 14.96 0.993 0.59 0.41 0.23 0.20 117 0.24 0.26 0.92 10.54 0.173 1.03 0.20 0.17 0.24 118 0.04 0.79 0.31 7.23 0.613 2.93 0.60 0.26 0.04 119 0.09 0.57 0.28 15.69 0.146 0.81 0.96 0.18 0.04 120 0.06 0.27 0.71 8.04 0.121 0.75 0.16 0.09 0.20 121 0.03 0.13 0.65 14.25 0.842 0.46 0.45 0.40 0.23 122 0.25 0.02 0.78 6.38 0.170 2.77 0.71 0.29 0.23 123 0.10 0.22 0.56 14.90 0.439 2.21 0.30 0.18 0.15 124 0.25 0.22 0.69 5.34 0.500 3.21 0.05 0.24 0.19 125 0.08 0.66 0.62 14.29 0.666 0.21 0.74 0.13 0.20 126 0.11 0.23 0.20 7.25 0.295 2.62 0.28 0.26 0.13 127 0.02 0.77 0.52 14.51 0.203 3.28 0.46 0.07 0.19 128 0.03 0.58 0.25 7.90 0.724 3.29 0.63 0.21 0.21 129 0.26 0.71 0.84 17.89 0.210 0.46 0.14 0.36 0.03 130 0.21 0.64 0.58 9.84 0.986 2.52 0.78 0.18 0.11 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 101 - 0.140 - - 1.17 - - 102 - 1.860 - - 3.80 - - 103 1.404 1.731 - - 4.68 - - 104 1.667 1.445 - - 3.01 - - 105 0.575 1.664 - - 0.40 - - 106 1.760 0.058 - - 3.27 - - 107 1.915 0.313 - - 3.63 - - 108 1.701 1.081 - - 0.65 - - 109 - - 1.638 - 0.80 - - 110 - - 1.980 -- 0.86 - - 111 - - 0.209 - 4.82 - - 112 - - 1.015 - 4.72 - - 113 - - 1.072 - 2.21 - - 114 - - 0.075 - 1.31 - - 115 1.592 - 0.651 - 3.56 - - 116 0.673 - 0.501 - 3.42 - - 117 1.451 - 0.278 - 2.48 - - 118 0.584 - 1.652 - 2.31 - - 119 1.764 - 1.303 - 2.20 - - 120 1.626 - 1.925 - 1.37 - - 121 - 1.168 0.162 - 3.77 - - 122 - 0.784 1.701 - 3.87 - - 123 - 0.018 0.215 - 0.84 - - 124 - 1.470 0.326 - 1.03 - - 125 - 0.880 0.754 - 1.34 - - 126 - 0.911 0.183 - 3.44 - - 127 1.756 1.252 0.281 - 1.69 - - 128 0.436 1.545 0.696 - 4.86 - - 129 0.861 1.463 1.103 - 4.96 - - 130 1.714 0.693 1.188 - 3.68 - - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 101 0.0264 0.004 0.006 5 157 8 102 0.0258 0.001 0.007 5 155 21 103 0.0011 0.002 0.010 6 164 39 104 0.0216 0.004 0.019 0 164 22 105 0.0080 0.002 0.005 5 155 22 106 0.0298 0.008 0.010 0 167 23 107 0.0228 0.007 0.014 3 177 30 108 0.0264 0.006 0.003 6 162 33 109 0.0060 0.004 0.012 6 151 25 110 0.0016 0.004 0.019 1 146 24 111 0.0229 0.010 0.002 5 174 10 112 0.0058 0.009 0.015 0 139 17 113 0.0199 0.006 0.007 0 143 22 114 0.0155 0.009 0.005 6 164 12 115 0.0024 0.001 0.013 4 155 31 116 0.0209 0.009 0.010 6 168 15 117 0.0208 0.004 0.012 7 132 26 118 0.0271 0.003 0.005 3 149 28 119 0.0205 0.004 0.017 3 146 29 120 0.0107 0.010 0.015 0 152 39 121 0.0227 0.001 0.014 6 168 21 122 0.0219 0.009 0.003 1 174 27 123 0.0029 0.008 0.006 4 171 16 124 0.0205 0.002 0.001 1 137 27 125 0.0256 0.003 0.015 7 151 26 126 0.0134 0.005 0.005 5 164 16 127 0.0234 0.006 0.016 5 155 38 128 0.0210 0.005 0.018 6 151 26 129 0.0158 0.005 0.005 0 131 35 130 0.0185 0.009 0.004 7 146 37 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 131 0.14 0.64 0.53 7.51 0.891 2.28 0.93 0.09 0.03 132 0.13 0.55 0.55 15.34 0.760 0.90 0.91 0.49 0.12 133 0.28 0.28 0.92 11.68 0.928 2.74 0.07 0.09 0.21 134 0.26 0.06 0.70 7.24 0.721 0.67 0.70 0.02 0.04 135 0.16 0.18 0.56 6.61 0.491 2.41 0.19 0.20 0.03 136 0.22 0.10 0.77 14.08 0.069 2.49 0.35 0.08 0.03 137 0.12 0.10 0.81 14.55 0.288 0.33 0.52 0.05 0.25 138 0.23 0.04 0.54 12.41 0.988 0.38 0.05 0.03 0.03 139 0.23 0.20 0.63 5.54 0.016 2.09 0.74 0.20 0.07 140 0.05 0.04 0.94 11.20 0.684 3.25 0.95 0.46 0.20 141 0.24 0.61 0.95 14.26 0.833 1.64 0.54 0.25 0.15 142 0.01 0.61 0.52 6.09 0.811 3.37 0.79 0.22 0.22 143 0.06 0.30 0.33 17.26 0.956 1.30 0.10 0.30 0.04 144 0.18 0.35 0.64 12.88 0.093 1.45 0.25 0.15 0.02 145 0.04 0.62 0.93 10.57 0.068 1.69 0.12 0.20 0.15 146 0.03 0.20 0.26 8.05 0.211 1.43 0.50 0.11 0.25 147 0.09 0.12 0.89 9.42 0.336 1.72 0.26 0.03 0.04 148 0.18 0.65 0.29 6.32 0.302 0.45 0.70 0.15 0.10 149 0.11 0.12 0.34 9.76 0.454 0.40 0.71 0.38 0.13 150 0.12 0.34 0.92 17.51 0.620 1.00 0.11 0.16 0.10 151 0.02 0.79 0.27 14.38 0.136 1.70 0.70 0.37 0.09 152 0.19 0.56 0.68 11.14 0.818 0.27 0.35 0.21 0.18 153 0.16 0.31 0.81 5.80 0.037 1.20 0.39 0.33 0.10 154 0.01 0.68 0.93 15.75 0.107 0.60 0.16 0.15 0.03 155 0.15 0.39 0.51 12.78 0.363 1.23 0.95 0.34 0.18 156 0.08 0.07 0.21 7.67 0.645 0.90 0.67 0.32 0.16 157 0.04 0.78 0.32 17.99 0.293 0.72 0.61 0.26 0.16 158 0.29 0.04 0.68 15.40 0.139 3.45 0.62 0.08 0.15 159 0.18 0.07 0.38 10.97 0.022 0.30 0.04 0.18 0.20 160 0.27 0.35 0.89 8.87 0.266 0.63 0.67 0.24 0.15 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 131 0.647 1.902 1.623 - 4.99 - - 132 1.348 1.760 0.077 - 3.27 - - 133 - - - 0.962 4.97 - - 134 - - - 1.168 4.50 - - 135 - - - 1.762 1.05 - - 136 - - - 0.437 3.44 - - 137 - - - 1.831 1.30 - - 138 - - - 0.643 1.01 - - 139 0.032 - - 0.561 4.23 - - 140 0.020 - - 1.225 0.56 - - 141 0.800 - - 0.314 3.59 - - 142 0.091 - - 1.513 0.57 - - 143 0.542 - - 1.455 2.60 - - 144 1.809 - - 1.849 1.78 - - 145 - 1.395 - 1.367 4.55 - - 146 - 0.851 - 0.674 0.52 - - 147 - 1.029 - 0.440 0.85 - - 148 - 1.604 - 0.336 4.77 - - 149 - 1.249 - 0.028 4.27 - - 150 - 1.610 - 1.176 0.97 - - 151 - - 1.696 0.475 1.32 - - 152 - - 0.524 1.620 4.58 - - 153 - - 0.473 0.262 0.29 - - 154 - - 1.208 1.053 2.06 - - 155 - - 1.419 0.689 1.93 - - 156 - - 1.769 0.830 1.48 - - 157 - 1.492 0.925 1.141 2.35 - - 158 - 0.991 1.568 0.313 1.35 - - 159 - 1.284 1.367 0.995 4.86 - - 160 - 0.032 1.984 - 1.878 4.93 - - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 131 0.0237 0.006 0.003 0 174 1 132 0.0266 0.004 0.006 0 143 36 133 0.0078 0.006 0.013 3 132 16 134 0.0215 0.007 0.018 3 167 14 135 0.0033 0.004 0.001 7 177 25 136 0.0231 0.004 0.015 5 139 17 137 0.0011 0.008 0.019 5 131 26 138 0.0072 0.004 0.010 5 180 17 139 0.0217 0.003 0.004 7 164 19 140 0.0246 0.006 0.006 3 137 15 141 0.0111 0.009 0.015 6 176 22 142 0.0061 0.004 0.017 4 157 24 143 0.0191 0.010 0.009 4 161 29 144 0.0161 0.008 0.017 0 138 39 145 0.0220 0.006 0.009 6 167 36 146 0.0020 0.003 0.010 6 176 21 147 0.0254 0.009 0.018 2 167 16 148 0.0131 0.007 0.010 1 168 28 149 0.0196 0.007 0.001 1 131 19 150 0.0102 0.005 0.009 5 135 35 151 0.0251 0.006 0.020 5 157 28 152 0.0296 0.002 0.012 6 150 26 153 0.0184 0.008 0.011 6 142 13 154 0.0168 0.005 0.014 7 135 28 155 0.0048 0.006 0.007 1 132 26 156 0.0223 0.003 0.017 6 161 31 157 0.0196 0.009 0.001 4 174 36 158 0.0068 0.010 0.015 3 175 27 159 0.0233 0.007 0.016 5 141 42 160 0.0201 0.009 0.003 4 174 42 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 161 0.19 0.75 0.45 13.56 0.218 2.24 0.39 0.43 0.09 162 0.21 0.37 0.97 16.56 0.721 2.96 0.02 0.43 0.10 163 0.27 0.24 0.30 15.55 0.602 2.24 0.39 0.38 0.02 164 0.18 0.63 0.7 8.38 0.691 2.83 0.35 0.47 0.04 165 0.18 0.24 0.45 12.52 0.337 2.54 0.23 0.12 0.25 166 0.23 0.10 0.21 6.25 0.857 0.80 0.83 0.46 0.25 167 0.26 0.49 0.65 13.37 0.602 2.04 0.05 0.45 0.11 168 0.25 0.49 0.85 12.46 0.906 2.46 0.19 0.26 0.05 169 0.29 0.77 0.27 7.78 0.110 1.49 0.58 0.03 0.02 170 0.18 0.40 0.78 16.70 0.537 0.22 0.58 0.43 0.10 171 0.19 0.44 0.64 11.08 0.034 1.42 0.51 0.16 0.13 172 0.20 0.75 0.54 8.30 0.926 2.89 0.21 0.10 0.20 173 0.08 0.41 0.32 12.57 0.052 2.43 0.49 0.18 0.01 174 0.07 0.49 0.27 15.46 0.749 1.19 0.73 0.08 0.15 175 0.25 0.07 0.27 14.93 0.869 1.93 0.75 0.21 0.07 176 0.30 0.59 0.56 8.71 0.735 0.79 0.39 0.24 0.11 177 0.15 0.34 0.23 7.61 0.679 0.51 0.96 0.33 0.23 178 0.05 0.78 0.73 16.09 0.047 2.23 0.83 0.41 0.03 179 0.11 0.59 0.75 12.48 0.661 0.42 0.33 0.39 0.06 180 0.12 0.05 0.54 14.09 0.366 2.83 0.76 0.44 0.17 181 0.05 0.18 0.78 12.39 0.497 0.64 0.99 0.23 0.20 182 0.13 0.48 0.93 5.14 0.880 1.55 0.36 0.42 0.10 183 0.16 0.42 0.87 16.27 0.869 3.40 0.20 0.19 0.21 184 0.11 0.66 0.86 11.14 0.788 2.33 0.81 0.45 0.11 185 0.07 0.29 0.36 7.11 0.974 1.09 0.08 0.12 0.02 186 0.14 0.74 0.86 15.01 0.764 2.46 0.80 0.12 0.12 187 0.12 0.33 0.62 13.30 0.498 0.95 0.84 0.11 0.03 188 0.26 0.09 0.30 12.80 0.503 0.93 0.04 0.27 0.07 189 0.21 0.29 0.58 11.32 0.126 0.26 0.69 0.25 0.06 190 0.09 0.80 0.93 13.34 0.694 1.68 0.18 0.49 0.22 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 161 - 0.907 0.105 0.625 0.75 - - 162 - 0.587 0.391 1.902 1.12 - - 163 1.594 - 0.512 0.388 0.49 - - 164 0.508 - 1.154 0.759 0.46 - - 165 1.338 - 1.981 1.673 2.62 - - 166 1.161 - 0.663 1.823 3.82 - - 167 0.476 - 1.885 0.880 3.27 - - 168 1.154 - 0.315 1.493 2.53 - - 169 1.447 0.255 - 0.337 0.84 - - 170 0.041 1.529 - 0.098 2.23 - - 171 0.597 0.681 - 0.450 1.13 - - 172 1.775 0.354 - 1.066 1.51 - - 173 0.262 1.210 - 0.612 2.65 - - 174 1.757 1.947 - 1.763 3.71 - - 175 1.909 0.205 1.307 1.158 3.80 - - 176 0.377 1.649 1.502 0.482 2.23 - - 177 0.853 0.995 0.970 0.450 0.70 - - 178 1.998 1.905 1.364 0.722 3.17 - - 179 0.493 0.040 1.344 1.935 1.58 - - 180 0.988 0.083 0.597 1.782 4.79 - - 181 0.188 - - - - 3.17 - 182 0.712 - - - - 0.69 - 183 0.283 - - - - 1.48 - 184 0.562 - - - - 2.43 - 185 1.198 - - - - 0.30 - 186 1.887 - - - - 1.56 - 187 - 0.798 - - - 2.98 - 188 - 1.187 - - - 3.75 - 189 - 1.520 - - - 3.12 - 190 - 1.477 - - - 2.74 - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 161 0.0220 0.006 0.009 3 154 18 162 0.0238 0.004 0.003 4 156 34 163 0.0208 0.002 0.010 3 159 29 164 0.0230 0.003 0.009 4 142 33 165 0.0107 0.006 0.015 2 155 47 166 0.0088 0.010 0.005 3 178 44 167 0.0123 0.008 0.007 2 162 32 168 0.0162 0.007 0.006 5 137 33 169 0.0157 0.007 0.009 3 178 24 170 0.0062 0.006 0.005 0 165 27 171 0.0273 0.002 0.017 5 175 19 172 0.0294 0.008 0.014 2 135 37 173 0.0078 0.003 0.013 4 173 26 174 0.0170 0.010 0.019 6 143 50 175 0.0218 0.003 0.011 5 171 40 176 0.0029 0.004 0.013 2 161 44 177 0.0156 0.003 0.005 3 140 36 178 0.0098 0.003 0.010 3 137 57 179 0.0103 0.002 0.018 2 177 35 180 0.0120 0.002 0.013 2 165 37 181 0.0255 0.008 0.014 5 154 7 182 0.0009 0.009 0.017 2 145 12 183 0.0223 0.002 0.009 1 142 10 184 0.0260 0.001 0.015 2 173 12 185 0.0067 0.008 0.004 2 165 18 186 0.0192 0.004 0.010 6 145 23 187 0.0289 0.010 0.013 3 142 18 188 0.0008 0.006 0.017 6 134 23 189 0.0196 0.004 0.011 2 147 22 190 0.0209 0.008 0.019 2 135 19 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 191 0.27 0.33 0.81 10.22 0.553 1.33 0.31 0.39 0.14 192 0.13 0.68 0.49 12.62 0.520 1.98 0.42 0.14 0.03 193 0.05 0.18 0.64 12.12 0.945 1.44 0.36 0.13 0.09 194 0.13 0.27 0.34 13.18 0.177 2.50 0.96 0.05 0.03 195 0.04 0.41 0.65 13.48 0.033 1.27 0.56 0.05 0.18 196 0.16 0.49 0.63 10.87 0.351 0.56 0.50 0.07 0.13 197 0.30 0.37 0.56 16.37 0.473 3.09 0.60 0.01 0.10 198 0.12 0.32 0.71 8.10 0.222 1.67 0.69 0.28 0.15 199 0.15 0.58 0.92 16.48 0.429 2.40 0.13 0.32 0.01 200 0.20 0.67 0.70 7.17 0.464 3.16 0.73 0.30 0.24 201 0.23 0.44 0.70 16.85 0.149 3.36 0.86 0.37 0.09 202 0.18 0.15 0.39 10.83 0.303 0.78 0.34 0.45 0.22 203 0.16 0.46 0.44 13.07 0.771 1.49 0.98 0.47 0.13 204 0.26 0.07 0.72 14.80 0.395 1.65 0.66 0.34 0.25 205 0.29 0.80 0.69 7.58 0.508 0.75 0.69 0.23 0.18 206 0.05 0.18 0.63 15.23 0.445 1.50 0.90 0.06 0.13 207 0.08 0.42 0.40 9.31 0.031 1.73 0.65 0.23 0.05 208 0.05 0.23 0.67 7.59 0.616 0.90 0.76 0.19 0.02 209 0.04 0.66 0.52 14.30 0.038 1.78 0.57 0.33 0.02 210 0.30 0.78 0.20 14.34 0.625 0.53 0.42 0.34 0.22 211 0.20 0.08 0.80 11.98 0.714 1.52 0.12 0.36 0.13 212 0.13 0.39 0.56 11.60 0.635 0.93 0.53 0.09 0.17 213 0.20 0.41 0.98 17.71 0.248 1.56 0.99 0.18 0.07 214 0.19 0.78 0.32 15.07 0.366 1.18 0.83 0.06 0.15 215 0.08 0.22 0.84 7.95 0.323 2.51 0.39 0.12 0.01 216 0.09 0.15 0.80 7.38 0.467 1.76 0.48 0.30 0.09 217 0.05 0.44 0.49 11.21 0.633 1.71 0.48 0.27 0.11 218 0.18 0.19 0.57 17.16 0.145 3.39 0.19 0.44 0.03 219 0.15 0.05 0.91 10.31 0.857 1.41 0.95 0.24 0.18 220 0.07 0.29 0.98 14.37 0.096 3.39 0.12 0.08 0.15 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 191 - 0.724 - - - 4.15 - 192 - 0.919 - - - 4.15 - 193 1.414 1.737 - - - 1.99 - 194 1.662 1.868 - - - 4.10 - 195 1.995 0.968 - - - 4.86 - 196 0.112 0.729 - - - 1.15 - 197 0.652 1.798 - - - 4.10 - 198 0.270 1.867 - - - 0.94 - 199 - - 1.997 - - 0.51 - 200 - - 1.618 - - 4.42 - 201 - - 0.590 - - 2.15 - 202 - - 0.612 - - 0.32 - 203 - - 0.376 - - 2.88 - 204 - - 0.521 - - 1.81 - 205 1.236 - 1.723 - - 3.54 - 206 0.913 - 1.670 - - 2.48 - 207 1.757 - 0.032 - - 0.25 - 208 0.433 - 1.456 - - 3.23 - 209 0.603 - 0.634 - - 1.05 - 210 0.952 - 1.214 - - 2.47 - 211 - 1.529 0.895 - - 4.41 - 212 - 0.011 0.342 - - 1.20 - 213 - 0.565 0.231 - - 1.71 - 214 - 0.844 1.209 - - 2.64 - 215 - 0.545 1.976 - - 0.98 - 216 - 0.338 1.198 - - 2.99 - 217 0.551 0.877 1.540 - - 3.18 - 218 1.440 0.847 0.689 - - 0.69 - 219 0.559 1.905 1.286 - - 2.00 - 220 1.563 0.765 0.050 - - 1.47 - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 191 0.0145 0.002 0.001 7 151 16 192 0.0106 0.002 0.011 2 172 12 193 0.0041 0.009 0.016 1 176 30 194 0.0202 0.010 0.014 6 166 32 195 0.0238 0.009 0.002 1 144 29 196 0.0256 0.009 0.005 6 139 18 197 0.0051 0.008 0.011 3 177 24 198 0.0023 0.006 0.016 4 137 26 199 0.0126 0.005 0.007 2 147 24 200 0.0009 0.003 0.010 6 134 25 201 0.0218 0.003 0.004 7 175 14 202 0.0264 0.005 0.013 1 149 11 203 0.0097 0.003 0.015 4 159 15 204 0.0259 0.002 0.016 5 156 19 205 0.0108 0.008 0.015 3 170 33 206 0.0045 0.004 0.016 3 176 26 207 0.0165 0.007 0.007 0 180 25 208 0.0273 0.003 0.014 5 132 25 209 0.0019 0.003 0.015 5 161 16 210 0.0249 0.001 0.015 3 145 30 211 0.0022 0.005 0.012 4 161 25 212 0.0035 0.009 0.013 1 136 15 213 0.0086 0.002 0.004 3 150 12 214 0.0129 0.001 0.010 5 179 24 215 0.0118 0.010 0.011 2 176 33 216 0.0295 0.007 0.003 4 169 26 217 0.0022 0.006 0.010 3 160 37 218 0.0138 0.005 0.002 1 178 33 219 0.0153 0.007 0.013 0 150 35 220 0.0012 0.002 0.012 7 154 29 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 221 0.02 0.37 0.64 14.25 0.193 0.58 0.99 0.11 0.01 222 0.25 0.18 0.97 14.38 0.985 2.32 0.46 0.27 0.23 223 0.28 0.76 0.24 12.56 0.823 3.16 0.82 0.23 0.15 224 0.06 0.03 0.70 13.02 0.518 2.47 0.41 0.14 0.21 225 0.26 0.58 0.62 7.33 0.417 1.44 0.08 0.43 0.02 22.6 0.26 0.35 0.30 12.90 0.374 2.84 0.16 0.03 0.01 227 0.16 0.38 0.39 7.95 0.202 2.75 0.48 0.33 0.04 228 0.06 0.14 0.34 16.35 0.737 2.34 0.38 0.27 0.04 229 0.19 0.68 0.85 10.11 0.334 1.07 0.70 0.02 0.24 230 0.22 0.32 0.98 6.50 0.315 3.32 0.29 0.22 0.23 231 0.24 0.48 0.99 9.89 0.019 0.32 0.46 0.07 0.21 232 0.22 0.65 0.35 11.64 0.776 3.05 0.55 0.22 0.14 233 0.10 0.30 0.93 9.52 0.421 2.71 0.39 0.33 0.21 234 0.26 0.48 1.00 14.56 0.306 0.47 0.34 0.10 0.16 235 0.09 0.28 0.83 5.06 0.252 2.34 0.22 0.41 0.06 236 0.25 0.36 0.69 11.45 0.104 1.20 0.86 0.21 0.12 237 0.13 0.19 0.84 11.98 0.189 1.44 0.62 0.39 0.16 238 0.25 0.04 0.76 11.14 0.848 0.89 0.81 0.40 0.05 239 0.13 0.17 0.31 13.18 0.418 0.63 0.78 0.38 0.08 240 0.15 0.06 0.97 9.52 0.730 1.79 0.38 0.01 0.23 241 0.14 0.37 0.59 11.08 0.132 0.52 0.40 0.20 0.22 242 0.17 0.56 0.66 9.08 0.438 1.24 0.23 0.13 0.12 243 0.22 0.15 0.64 8.14 0.510 1.77 0.17 0.22 0.02 244 0.22 0.54 0.79 5.96 0.671 1.54 0.56 0.12 0.24 245 0.27 0.44 0.99 6.88 0.754 1.67 0.25 0.26 0.01 246 0.05 0.51 0.31 8.74 0.595 1.62 0.07 0.06 0.03 247 0.21 0.61 0.60 15.93 0.528 2.46 0.34 0.17 0.12 248 0.15 0.23 0.96 13.52 0.402 2.07 0.42 0.28 0.14 249 0.10 0.79 0.43 5.61 0.046 3.16 0.14 0.06 0.03 250 0.15 0.24 0.89 16.22 0.789 0.26 0.81 0.40 0.13 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 221 0.118 1.041 0.597 - - 0.72 - 222 0.915 0.451 1.641 - - 1.38 - 223 - - - 0.338 - 2.68 - 224 - - - 0.103 - 3.76 - 225 - - - 0.754 - 1.52 - 226 - - - 0.945 - 2.34 - 227 - - - 0.339 - 0.58 - 228 - - - 1.617 - 2.73 - 229 0.410 - - 0.455 - 3.20 - 230 0.260 - - 0.507 - 1.13 - 231 0.398 - - 1.461 - 0.59 - 232 1.468 - - 1.955 - 3.11 - 233 0.153 - - 1.729 - 3.26 - 234 0.146 - - 0.403 - 4.91 - 235 - 0.893 - 0.643 - 4.92 - 236 - 1.458 - 0.163 - 2.55 - 237 - 1.227 - 1.607 - 1.75 - 238 - 0.846 - 0.642 - 4.15 - 239 - 1.017 - 1.958 - 4.18 - 240 - 0.399 - 0.226 - 1.03 - 241 - - 1.741 0.097 - 3.51 - 242 - - 1.531 0.248 - 1.25 - 243 - - 1.912 1.371 - 0.65 - 244 - - 0.554 0.116 - 3.33 - 245 - - 0.145 0.116 - 1.31 - 246 - - 0.350 0.219 - 3.42 - 247 - 0.335 1.823 0.900 - 1.63 - 248 - 0.570 0.249 1.891 - 4.74 - 249 - 1.069 1.298 0.885 - 4.80 - 250 - 0.499 0.648 0.540 - 1.04 - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M % 221 0.0120 0.010 0.006 2 168 20 222 0.0271 0.003 0.018 6 143 32 223 0.0277 0.007 0.009 3 159 9 224 0.0230 0.006 0.014 3 168 13 225 0.0086 0.004 0.019 4 147 18 226 0.0089 0.009 0.002 2 174 19 227 0.0194 0.004 0.009 3 177 10 228 0.0204 0.008 0.016 2 134 26 229 0.0067 0.004 0.002 2 173 18 230 0.0034 0.009 0.011 0 170 17 231 0.0054 0.008 0.012 4 180 28 232 0.0227 0.010 0.020 1 179 36 233 0.0212 0.002 0.013 1 170 29 234 0.0099 0.003 0.016 7 132 18 235 0.0147 0.005 0.018 6 142 24 236 0.0153 0.008 0.014 4 177 19 237 0.0220 0.006 0.012 0 165 33 238 0.0147 0.009 0.017 4 160 25 239 0.0184 0.005 0.018 4 138 29 240 0.0283 0.004 0.020 3 153 13 241 0.0096 0.004 0.010 2 157 26 242 0.0171 0.001 0.015 0 178 19 243 0.0012 0.006 0.011 1 169 37 244 0.0164 0.004 0.007 5 157 15 245 0.0286 0.003 0.016 6 170 9 246 0.0176 0.010 0.009 5 136 14 247 0.0082 0.010 0.018 1 133 33 248 0.0253 0.002 0.004 1 139 31 249 0.0195 0.002 0.012 2 155 34 250 0.0158 0.008 0.018 4 161 25 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 251 0.12 0.76 0.21 17.18 0.976 1.07 0.81 0.49 0.03 252 0.10 0.30 0.26 12.84 0.941 3.40 0.46 0.01 0.05 253 0.04 0.26 0.90 13.98 0.512 3.38 0.57 0.34 0.15 254 0.05 0.54 0.82 5.66 0.537 0.52 1.00 0.19 0.06 255 0.21 0.61 0.25 11.51 0.332 2.45 0.09 0.19 0.09 256 0.20 0.73 0.69 16.68 0.764 0.51 0.65 0.04 0.21 257 0.25 0.40 0.41 12.40 0.647 2.29 0.54 0.12 0.25 258 0.18 0.63 0.46 15.82 0.315 2.32 0.10 0.39 0.18 259 0.07 0.15 0.33 12.23 0.620 1.77 0.15 0.49 0.07 260 0.17 0.77 0.67 12.23 0.886 1.68 0.52 0.11 0.02 261 0.30 0.03 0.95 13.70 0.948 1.55 0.57 0.39 0.09 262 0.25 0.13 0.66 14.65 0.159 0.84 0.13 0.03 0.01 263 0.12 0.57 0.85 6.34 0.834 0.64 0.02 0.42 0.22 264 0.02 0.03 0.99 12.60 0.319 0.38 0.09 0.25 0.20 265 0.18 0.73 0.95 11.85 0.441 2.87 0.65 0.17 0.03 266 0.12 0.21 1.00 8.44 0.550 0.95 0.08 0.35 0.04 267 0.23 0.67 0.21 6.70 0.468 0.67 0.19 0.22 0.05 268 0.02 0.05 0.84 11.14 0.047 1.52 0.31 0.19 0.04 269 0.04 0.55 0.78 6.58 0.613 2.94 0.30 0.19 0.08 270 0.08 0.09 0.29 10.30 0.502 2.72 0.47 0.36 0.14 271 0.09 0.10 0.82 7.14 0.545 0.32 0.66 0.15 0.17 272 0.04 0.46 0.65 8.10 0.588 1.81 0.23 0.44 0.01 273 0.02 0.26 0.86 10.97 0.960 3.38 0.98 0.20 0.11 274 0.27 0.16 0.92 13.67 0.010 1.15 0.78 0.30 0.19 275 0.16 0.79 0.67 13.99 0.551 1.18 0.94 0.19 0.09 276 0.08 0.48 0.41 9.82 0.933 2.93 0.82 0.26 0.12 277 0.13 0.27 0.39 5.54 0.494 0.92 0.73 0.21 0.13 278 0.11 0.41 0.89 5.52 0.563 2.83 0.52 0.18 0.08 279 0.27 0.79 0.97 7.62 0.973 3.21 0.53 0.34 0.05 280 0.27 0.10 0.50 16.16 0.574 1.50 0.09 0.13 0.11 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 251 - 1.532 1.968 1.534 - 2.25 - 252 - 1.831 0.924 1.529 - 0.42 - 253 0.803 - 1.189 1.203 - 1.98 - 254 1.794 - 0.446 1.234 - 3.76 - 255 1.178 - 1.347 0.282 - 4.92 - 256 0.669 - 1.568 0.006 - 2.30 - 257 1.865 - 1.787 0.110 - 2.35 - 258 1.510 - 1.686 1.249 - 4.24 - 259 0.248 0.985 - 1.109 - 2.42 - 260 0.747 1.654 - 0.344 - 3.26 - 261 0.690 1.627 - 0.621 - 3.56 - 262 0.733 0.594 - 0.632 - 2.61 - 263 1.562 1.228 - 0.042 - 4.34 - 264 1.829 0.192 - 1.507 - 0.81 - 265 0.239 0.167 0.176 1.724 - 0.82 - 266 0.432 0.819 0.623 0.357 - 1.19 - 267 1.083 1.821 0.789 1.070 - 1.12 - 268 1.896 1.854 0.352 0.550 - 2.25 - 269 0.526 1.566 0.959 1.438 - 1.33 - 270 1.625 0.646 0.293 0.424 - 4.80 - 271 0.875 - - - 4.92 4.72 - 272 1.948 - - - 1.30 2.68 - 273 0.540 - - - 1.21 0.25 - 274 0.300 - - - 3.89 1.47 - 275 1.883 - - - 1.33 0.73 - 276 0.993 - - - 4.81 2.10 - 277 - 1.883 - - 1.49 2.39 - 278 - 1.083 - - 2.60 3.16 - 279 - 1.692 - - 4.94 1.25 - 280 - 0.390 - - 0.53 3.06 - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M % 251 0.0093 0.002 0.019 6 158 51 252 0.0095 0.004 0.003 6 174 45 253 0.0271 0.009 0.015 4 137 31 254 0.0121 0.005 0.004 2 176 33 255 0.0193 0.006 0.004 1 166 28 256 0.0288 0.008 0.013 2 162 31 257 0.0210 0.007 0.017 5 141 36 258 0.0208 0.006 0.015 1 156 47 259 0.0233 0.007 0.002 4 134 30 260 0.0086 0.004 0.004 4 154 31 261 0.0164 0.006 0.018 6 142 29 262 0.0124 0.005 0.012 2 177 23 263 0.0212 0.006 0.012 1 137 36 264 0.0232 0.006 0.005 6 148 38 265 0.0132 0.004 0.008 5 140 27 266 0.0018 0.007 0.006 4 139 22 267 0.0133 0.002 0.017 2 173 44 268 0.0283 0.003 0.008 4 146 48 269 0.0116 0.002 0.015 3 134 41 270 0.0186 0.004 0.015 5 141 37 271 0.0142 0.009 0.006 0 144 19 272 0.0086 0.002 0.012 6 172 29 273 0.0114 0.004 0.002 4 151 12 274 0.0184 0.009 0.011 3 159 9 275 0.0239 0.005 0.016 6 150 22 276 0.0087 0.007 0.006 4 150 14 277 0.0127 0.002 0.006 4 164 21 278 0.0157 0.003 0.003 0 168 15 279 0.0279 0.008 0.002 3 140 23 280 0.0296 0.003 0.002 3 157 11 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 281 0.21 0.16 0.55 9.60 0.692 0.45 0.04 0.45 0.24 282 0.04 0.07 1.00 11.83 0.171 1.18 0.69 0.47 0.03 283 0.15 0.09 0.50 14.04 0.827 1.50 0.42 0.37 0.05 284 0.05 0.48 0.93 7.76 0.514 0.83 0.03 0.06 0.24 285 0.13 0.33 0.95 16.76 0.069 0.36 0.37 0.20 0.10 286 0.20 0.30 0.84 13.00 0.319 1.12 0.28 0.46 0.06 287 0.07 0.65 0.86 13.75 0.599 2.61 0.10 0.27 0.21 288 0.13 0.07 0.49 10.48 0.256 2.63 0.64 0.29 0.02 289 0.03 0.40 0.39 7.51 0.118 2.29 0.27 0.19 0.06 290 0.17 0.72 0.43 15.69 0.023 1.04 0.79 0.38 0.04 291 0.20 0.13 0.48 6.91 0.801 1.64 0.08 0.29 0.18 292 0.08 0.05 0.80 17.97 0.794 0.25 0.43 0.32 0.17 293 0.05 0.36 0.87 7.79 0.338 2.92 0.21 0.41 0.24 294 0.07 0.15 0.95 13.30 0.768 2.54 0.73 0.47 0.10 295 0.22 0.08 0.52 6.30 0.424 1.85 0.35 0.41 0.06 296 0.18 0.40 0.65 17.17 0.631 0.29 0.39 0.17 0.22 297 0.19 0.21 0.79 17.72 0.737 2.30 0.20 0.39 0.16 298 0.20 0.55 0.42 12.37 0.565 2.34 0.59 0.25 0.10 299 0.15 0.51 0.61 11.99 0.964 3.24 0.42 0.41 0.11 300 0.16 0.74 0.43 14.49 0.270 2.76 0.04 0.31 0.03 301 0.02 0.34 0.54 17.69 0.808 2.03 0.73 0.35 0.19 302 0.13 0.74 0.43 6.51 0.925 0.51 0.88 0.21 0.18 303 0.29 0.64 0.34 11.22 0.948 2.58 0.81 0.05 0.08 304 0.15 0.30 0.56 16.62 0.212 1.09 0.84 0.27 0.22 305 0.27 0.76 0.55 7.85 0.066 2.15 0.82 0.32 0.08 306 0.15 0.73 0.98 8.57 0.328 0.23 0.59 0.10 0.08 307 0.17 0.07 0.90 16.38 0.324 1.35 0.49 0.02 0.09 308 0.15 0.21 1.00 16.52 0.413 3.37 0.79 0.02 0.17 309 0.19 0.26 0.36 7.00 0.945 0.84 0.92 0.50 0.17 310 0.09 0.10 0.43 11.53 0.243 3.12 0.70 0.40 0.06 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 281 - 1.822 - - 0.53 0.58 - 282 - 0.712 - - 4.25 2.69 - 283 0.574 0.683 - - 1.21 3.71 - 284 1.971 1.393 - - 2.64 0.50 - 285 0.951 0.559 - - 0.57 4.25 - 286 0.147 1.851 - - 1.46 2.28 - 287 1.251 1.941 - - 2.12 0.94 - 288 1.925 0.495 - - 1.71 1.80 - 289 - - 0.602 - 4.25 1.71 - 290 - - 0.709 - 4.21 4.71 - 291 - - 0.651 - 3.13 0.35 - 292 - - 1.113 - 0.25 4.68 - 293 - - 1.738 - 1.96 2.45 - 294 - - 0.233 - 0.29 2.57 - 295 1.277 - 1.252 - 4.05 4.16 - 296 1.752 - 1.482 - 0.48 1.73 - 297 1.867 - 1.586 - 0.75 1.61 - 298 0.258 - 1.229 - 4.10 3.06 - 299 1.616 - 0.091 - 4.93 0.46 - 300 1.633 - 1.842 - 2.47 2.65 - 301 - 0.207 0.156 - 0.70 4.02 - 302 - 0.750 0.712 - 3.68 1.40 - 303 - 0.823 1.165 - 0.99 1.22 - 304 - 1.106 1.196 - 1.43 0.25 - 305 - 0.272 1.475 - 1.84 4.92 - 306 - 0.980 1.667 - 1.38 4.80 - 307 0.959 1.913 1.452 - 4.15 3.97 - 308 0.239 1.730 1.484 - 2.05 1.60 - 309 0.234 0.142 0.479 - 1.62 4.15 - 310 0.586 0.789 1.078 - 4.41 1.21 - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 281 0.0006 0.008 0.018 3 149 19 282 0.0259 0.009 0.019 6 142 19 283 0.0106 0.004 0.010 7 139 17 284 0.0248 0.009 0.018 4 167 39 285 0.0186 0.006 0.010 4 131 19 286 0.0028 0.010 0.012 6 156 28 287 0.0166 0.006 0.012 1 172 36 288 0.0106 0.008 0.015 5 156 29 289 0.0243 0.008 0.010 1 134 17 290 0.0235 0.009 0.012 1 137 10 291 0.0029 0.007 0.017 3 140 13 292 0.0171 0.007 0.004 7 172 15 293 0.0018 0.009 0.009 4 160 20 294 0.0268 0.003 0.017 4 133 16 295 0.0125 0.004 0.016 3 167 34 296 0.0286 0.007 0.014 1 141 38 297 0.0256 0.002 0.015 6 133 31 298 0.0133 0.009 0.009 6 169 18 299 0.0016 0.009 0.019 6 179 21 300 0.0008 0.009 0.005 6 139 41 301 0.0209 0.008 0.002 4 177 15 302 0.0271 0.009 0.016 2 171 17 303 0.0147 0.006 0.015 0 174 22 304 0.0232 0.003 0.007 0 164 28 305 0.0032 0.005 0.015 4 143 26 306 0.0239 0.004 0.009 1 139 33 307 0.0065 0.006 0.005 2 180 40 308 0.0204 0.006 0.018 1 143 33 309 0.0012 0.006 0.008 7 131 14 310 0.0183 0.002 0.018 0 172 31 D-CRS: Difference between the creep rupture strength at 600°C for 100,000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100,000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 311 0.10 0.74 0.29 14.89 0.132 1.34 0.43 0.12 0.14 312 0.03 0.13 0.20 8.54 0.953 3.26 0.95 0.33 0.14 313 0.10 0.47 0.84 16.34 0.552 1.73 0.14 0.45 0.03 314 0.29 0.07 0.46 10.07 0.749 2.80 0.77 0.41 0.23 315 0.24 0.76 0.95 7.19 0.887 2.62 0.23 0.11 0.24 316 0.21 0.05 0.56 5.37 0.799 2.30 0.31 0.45 0.25 317 0.14 0.18 0.76 15.68 0.326 2.95 0.87 0.40 0.22 318 0.28 0.62 0.63 16.48 0.800 0.76 0.26 0.34 0.24 319 0.14 0.06 0.44 12.09 0.065 3.41 0.30 0.44 0.02 320 0.26 0.35 0.84 6.87 0.444 2.10 0.81 0.14 0.12 321 0.15 0.56 0.52 11.65 0.278 2.91 0.67 0.09 0.16 322 0.21 0.56 0.54 17.85 0.403 0.32 0.67 0.45 0.19 323 0.23 0.24 0.36 10.32 0.656 0.43 0.67 0.16 0.08 324 0.17 0.63 0.67 6.44 0.375 1.02 0.50 0.37 0.13 325 0.29 0.05 0.52 17.17 0.401 1.58 0.51 0.27 0.07 326 0.08 0.31 0.99 14.24 0.060 1.53 0.03 0.50 0.10 327 0.23 0.12 0.74 15.10 0.691 2.00 0.37 0.50 0.06 328 0.26 0.52 0.84 11.02 0.629 0.79 0.88 0.18 0.03 329 0.26 0.22 0.77 12.93 0.212 0.64 0.41 0.44 0.21 330 0.19 0.25 0.38 5.69 0.273 1.06 0.29 0.48 0.21 331 0.28 0.09 0.35 13.06 0.640 1.43 0.84 0.45 0.09 332 0.21 0.40 0.95 13.62 0.668 2.94 0.91 0.28 0.07 333 0.21 0.67 0.85 11.63 0.684 3.36 0.85 0.36 0.09 334 0.23 0.36 0.31 11.46 0.026 0.51 0.97 0.39 0.14 335 0.09 0.54 0.81 17.53 0.522 0.44 0.13 0.03 0.04 336 0.03 0.66 0.61 8.04 0.019 2.60 0.15 0.43 0.23 337 0.28 0.62 0.37 6.98 0.339 1.51 0.85 0.03 0.20 338 0.22 0.67 0.78 12.20 0.327 1.57 0.10 0.24 0.14 339 0.10 0.29 0.90 8.67 0.824 2.27 0.71 0.47 0.03 340 0.15 0.53 0.60 7.17 0.663 3.05 0.54 0.40 0.17 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 311 1.965 0.352 1.955 - 2.43 3.98 - 312 0.054 0.505 1.795 - 4.50 2.06 - 313 - - - 1.693 0.23 4.31 - 314 - - - 1.243 0.81 0.29 - 315 - - - 0.129 3.07 3.63 - 316 - - - 0.034 1.47 3.98 - 317 - - - 0.616 4.78 0.50 - 318 - - - 1.532 2.57 2.03 - 319 1.707 - - 0.482 1.32 2.97 - 320 1.592 - - 1.121 2.61 2.54 - 321 1.218 - - 1.121 3.24 4.73 - 322 0.266 - - 0.167 2.46 3.99 - 323 1.393 - - 1.917 1.86 4.32 - 324 0.313 - - 1.054 3.06 2.51 - 325 - 0.257 - 0.237 0.45 4.98 - 326 - 1.130 - 1.148 2.86 3.76 - 327 - 0.652 - 0.444 4.71 2.88 - 328 - 1.522 - 0.823 2.82 1.52 - 329 - 1.408 - 1.947 3.61 1.32 - 330 - 0.965 - 0.483 3.85 3.85 - 331 - - 1.949 1.098 2.78 1.15 - 332 - - 1.906 1.463 1.98 1.98 - 333 - - 0.919 0.267 3.09 0.85 - 334 - - 1.668 0.168 0.56 1.74 - 335 - - 1.800 0.808 3.05 3.71 - 336 - - 0.987 1.876 0.29 1.33 - 337 - 0.199 0.960 1.110 1.18 1.10 - 338 - 1.373 1.368 1.138 4.86 2.12 - 339 - 0.261 0.847 1.601 0.87 3.55 - 340 - 0.544 1.096 0.207 2.89 4.68 - STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 311 0.0076 0.003 0.018 5 169 47 312 0.0083 0.006 0.003 2 149 26 313 0.0161 0.003 0.009 5 141 18 314 0.0256 0.003 0.014 2 171 24 315 0.0026 0.003 0.015 1 168 14 316 0.0016 0.003 0.008 7 159 10 317 0.0027 0.004 0.019 6 172 12 318 0.0012 0.003 0.006 1 135 21 319 0.0218 0.005 0.005 2 151 24 320 0.0299 0.009 0.013 1 172 27 321 0.0206 0.001 0.007 6 175 30 322 0.0189 0.006 0.004 2 140 14 323 0.0199 0.009 0.009 4 168 33 324 0.0036 0.008 0.020 1 162 23 325 0.0100 0.002 0.014 1 151 16 326 0.0193 0.003 0.007 5 161 23 327 0.0266 0.010 0.016 6 170 18 328 0.0273 0.003 0.017 2 156 32 329 0.0012 0.003 0.019 3 148 40 330 0.0180 0.008 0.007 6 147 23 331 0.0281 0.009 0.007 6 156 35 332 0.0264 0.003 0.016 6 153 36 333 0.0086 0.008 0.013 6 166 16 334 0.0139 0.003 0.002 2 148 21 335 0.0224 0.006 0.011 6 151 31 336 0.0149 0.005 0.006 3 153 28 337 0.0166 0.008 0.005 6 132 24 338 0.0220 0.006 0.003 6 166 38 339 0.0262 0.004 0.018 0 131 33 340 0.0095 0.007 0.016 7 157 27 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 341 0.04 0.08 0.54 5.41 0.168 3.33 0.89 0.19 0.17 342 0.30 0.77 0.60 8.00 0.184 2.60 0.64 0.02 0.22 343 0.16 0.13 0.23 12.67 0.053 2.00 0.10 0.28 0.18 344 0.14 0.37 0.92 17.37 0.596 0.93 0.11 0.41 0.24 345 0.21 0.59 0.94 6.88 0.665 2.20 0.49 0.34 0.11 346 0.03 0.66 0.54 5.17 0.092 0.30 0.11 0.22 0.01 347 0.26 0.44 0.40 10.05 0.206 2.93 0.28 0.46 0.01 348 0.30 0.60 0.39 6.34 0.342 2.94 0.34 0.49 0.20 349 0.07 0.22 0.38 18.00 0.346 3.10 0.63 0.48 0.16 350 0.13 0.34 0.63 16.75 0.539 2.88 0.98 0.10 0.11 351 0.13 0.06 0.61 7.17 0.277 3.38 0.26 0.01 0.25 352 0.03 0.04 0.20 6.57 0.387 2.43 0.76 0.13 0.17 353 0.20 0.53 0.46 6.21 0.201 1.10 0.83 0.13 0.20 354 0.18 0.62 0.86 17.01 0.057 2.16 0.81 0.42 0.17 355 0.05 0.18 0.47 10.84 0.782 3.42 0.54 0.42 0.05 356 0.06 0.64 0.35 11.51 0.730 2.69 0.85 0.07 0.03 357 0.17 0.33 0.79 10.50 0.230 2.75 0.58 0.01 0.09 358 0.02 0.28 0.43 5.52 0.600 2.99 0.05 0.16 0.05 359 0.02 0.35 0.34 7.34 0.681 2.89 0.10 0.44 0.12 360 0.11 0.43 0.42 14.27 0.844 2.01 0.59 0.30 0.02 361 0.25 0.40 0.53 11.04 0.407 3.04 0.36 0.13 0.20 362 0.09 0.12 0.52 14.75 0.187 2.10 0.21 0.09 0.12 363 0.18 0.62 0.27 10.49 0.036 2.00 0.97 0.10 0.12 364 0.03 0.23 0.85 9.05 0.284 2.18 0.04 0.10 0.15 365 0.16 0.38 0.53 8.42 0.777 2.12 0.20 0.49 0.06 366 0.11 0.54 0.37 12.80 0.344 2.88 0.79 0.44 0.03 367 0.25 0.60 0.64 7.02 0.311 0.65 0.66 0.37 0.04 368 0.25 0.02 0.42 15.15 0.529 1.50 0.16 0.21 0.17 369 0.21 0.25 0.77 15.44 0.331 3.23 0.10 0.11 0.13 370 0.07 0.77 0.76 12.22 0.544 0.32 0.31 0.23 0.13 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 341 - 0.887 1.780 1.610 0.52 2.29 - 342 - 0.994 0.592 1.507 2.62 0.45 - 343 0.348 - 0.174 1.543 1.10 0.69 - 344 1.622 - 0.191 0.385 4.84 2.25 - 345 1.781 - 1.336 1.719 1.03 1.95 - 346 1.478 - 0.290 0.230 0.91 3.83 - 347 0.402 - 1.705 1.569 1.28 2.27 - 348 0.205 - 1.264 1.418 1.34 1.28 - 349 1.566 1.846 - 1.445 0.31 4.89 - 350 0.166 0.064 - 1.322 2.21 2.70 - 351 1.679 1.062 - 1.712 1.41 1.11 - 352 0.775 0.508 - 1.290 4.35 1.72 - 353 1.108 1.097 - 1.754 0.70 3.83 - 354 0.365 0.493 - 1.750 1.60 4.18 - 355 0.197 0.371 0.494 1.962 3.91 4.41 - 356 0.307 1.385 0.353 1.051 4.39 1.30 - 357 0.354 0.230 0.404 1.689 2.27 3.65 - 358 1.966 1.537 1.288 0.549 1.58 1.13 - 359 0.872 1.011 1.703 1.293 1.49 4.89 - 360 0.766 1.341 1.345 0.632 3.70 4.63 - 361 1.274 - - - - - 0.78 362 0.074 - - - - - 1.77 363 1.826 - - - - - 1.57 364 1.239 - - - - - 0.80 365 0.962 - - - - - 0.95 366 0.660 - - - - - 1.73 367 - 1.386 - - - - 1.95 368 - 0.581 - - - - 1.32 369 - 0.640 - - - - 1.31 370 - 0.253 - - - - 0.76 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M % 341 0.0268 0.009 0.015 4 170 44 342 0.0284 0.003 0.020 2 149 37 343 0.0094 0.005 0.019 6 146 30 344 0.0242 0.006 0.008 7 138 26 345 0.0236 0.005 0.014 5 180 51 346 0.0028 0.007 0.014 6 148 20 347 0.0164 0.004 0.004 1 169 40 348 0.0144 0.002 0.002 4 173 27 349 0.0075 0.005 0.002 5 161 43 350 0.0200 0.002 0.013 1 161 26 351 0.0026 0.009 0.003 5 177 40 352 0.0098 0.003 0.005 4 136 26 353 0.0222 0.005 0.008 5 164 42 354 0.0199 0.004 0.019 2 166 26 355 0.0128 0.008 0.004 2 170 30 356 0.0109 0.006 0.010 4 176 32 357 0.0239 0.005 0.003 6 165 26 358 0.0029 0.005 0.011 4 162 46 359 0.0019 0.004 0.009 0 146 50 360 0.0018 0.004 0.006 0 146 45 361 0.0121 0.010 0.016 3 137 24 362 0.0282 0.005 0.008 5 173 9 363 0.0151 0.002 0.008 6 133 26 364 0.0279 0.004 0.012 4 168 20 365 0.0018 0.010 0.008 3 156 18 366 0.0213 0.008 0.002 3 175 13 367 0.0223 0.002 0.020 6 153 22 368 0.0293 0.005 0.020 0 168 17 369 0.0077 0.009 0.018 6 146 16 370 0.0122 0.005 0.011 3 167 11 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 371 0.08 0.27 0.26 16.45 0.018 2.17 0.65 0.02 0.01 372 0.20 0.20 0.73 6.46 0.575 3.27 0.94 0.12 0.09 373 0.08 0.02 0.45 6.10 0.063 3.07 0.05 0.46 0.08 374 0.12 0.79 0.49 6.75 0.806 2.70 0.26 0.21 0.07 375 0.11 0.43 0.71 12.68 0.144 3.22 0.92 0.03 0.02 376 0.02 0.75 0.58 8.94 0.916 0.85 0.91 0.34 0.25 377 0.23 0.07 0.78 12.81 0.463 3.28 0.53 0.31 0.12 378 0.25 0.22 0.37 9.20 0.114 1.71 0.13 0.12 0.20 379 0.19 0.28 0.41 8.84 0.204 0.54 0.03 0.41 0.07 380 0.15 0.13 0.38 16.29 0.071 0.58 0.07 0.36 0.07 381 0.21 0.80 0.54 16.16 0.047 2.22 0.09 0.41 0.03 382 0.19 0.22 0.77 12.97 0.962 0.66 0.42 0.44 0.15 383 0.03 0.21 0.94 17.69 0.675 0.67 0.40 0.16 0.16 384 0.28 0.65 0.50 8.60 0.509 3.34 0.38 0.20 0.14 385 0.02 0.63 0.55 16.04 0.796 3.15 0.18 0.25 0.04 386 0.20 0.41 0.53 5.40 0.872 2.90 0.63 0.46 0.06 387 0.07 0.24 0.31 6.94 0.081 2.01 0.58 0.03 0.18 388 0.15 0.40 0.57 5.67 0.747 1.62 0.86 0.34 0.10 389 0.24 0.75 0.79 5.97 0.219 2.81 0.81 0.33 0.14 390 0.02 0.39 0.81 5.60 0.327 3.43 0.28 0.16 0.04 391 0.15 0.74 0.92 15.52 0.905 1.25 0.08 0.01 0.23 392 0.02 0.52 0.58 7.52 0.787 2.33 0.04 0.28 0.19 393 0.15 0.75 0.87 5.49 0.322 1.19 1.00 0.40 0.11 394 0.21 0.15 0.83 13.76 0.326 0.60 0.34 0.04 0.10 395 0.29 0.55 0.77 10.90 0.159 3.33 0.84 0.11 0.09 396 0.20 0.23 0.53 7.47 0.628 2.16 0.37 0.03 0.05 397 0.04 0.27 0.79 8.05 0.094 1.60 0.75 0.22 0.19 398 0.20 0.12 0.21 16.99 0.876 1.04 0.82 0.35 0.22 399 0.19 0.05 0.66 12.52 0.822 3.27 0.91 0.33 0.22 400 0.11 0.73 0.82 5.70 0.768 2.80 0.88 0.33 0.05 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 371 - 0.091 - - - - 0.28 372 - 0.838 - - - - 1.35 373 1.534 1.141 - - - - 0.98 374 1.298 0.693 - - - - 0.69 375 1.068 0.158 - - - - 1.96 376 1.546 0.191 - - - - 0.91 377 0.417 1.485 - - - - 1.75 378 1.320 1.709 - - - - 0.58 379 - - 1.218 - - - 0.70 380 - - 0.977 - - - 0.92 381 - - 0.050 - - - 0.94 382 - - 1.100 - - - 0.46 383 - - 0.792 - - - 0.99 384 - - 1.824 - - - 1.34 385 0.337 - 1.856 - - - 0.31 386 0.783 - 0.562 - - - 1.20 387 0.325 - 1.566 - - - 1.01 388 0.636 - 0.619 - - - 0.37 389 1.374 - 1.370 - - - 1.68 390 1.231 - 0.468 - - - 1.01 391 - 1.846 0.600 - - - 1.71 392 - 0.615 0.427 - - - 0.75 393 - 0.388 0.627 - - - 0.56 394 - 0.845 1.877 - - - 1.72 395 - 1.652 0.850 - - - 0.36 396 - 0.485 1.208 - - - 1.57 397 1.632 1.997 0.622 - - - 1.45 398 1.522 1.895 1.780 - - - 1.51 399 1.575 0.817 1.332 - - - 1.47 400 0.458 0.455 1.965 - - - 1.02 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 371 0.0084 0.009 0.016 3 158 12 372 0.0210 0.002 0.019 7 146 20 373 0.0002 0.004 0.017 3 159 31 374 0.0011 0.006 0.017 5 175 24 375 0.0184 0.009 0.005 1 172 23 376 0.0028 0.005 0.009 3 177 28 377 0.0239 0.004 0.005 0 143 23 378 0.0024 0.005 0.009 5 149 29 379 0.0226 0.007 0.008 3 146 21 380 0.0200 0.009 0.010 6 162 19 381 0.0048 0.003 0.020 3 175 11 382 0.0167 0.003 0.006 3 163 19 383 0.0058 0.003 0.014 2 153 12 384 0.0274 0.009 0.002 6 149 21 385 0.0167 0.003 0.005 5 178 28 386 0.0132 0.009 0.009 3 167 22 387 0.0125 0.009 0.014 2 145 25 388 0.0247 0.001 0.004 5 165 23 389 0.0299 0.002 0.017 3 153 31 390 0.0227 0.009 0.019 5 138 19 391 0.0138 0.004 0.017 7 147 31 392 0.0276 0.008 0.008 1 158 13 393 0.0149 0.005 0.008 6 150 21 394 0.0152 0.008 0.014 1 173 34 395 0.0091 0.006 0.014 2 158 30 396 0.0210 0.007 0.003 7 180 24 397 0.0016 0.009 0.008 5 168 42 398 0.0056 0.001 0.006 6 175 47 399 0.0133 0.001 0.014 4 178 38 400 0.0046 0.002 0.018 2 155 29 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 401 0.20 0.06 0.54 13.75 0.541 2.37 0.55 0.28 0.24 402 0.13 0.27 0.52 8.69 0.489 1.47 0.25 0.10 0.06 403 0.28 0.43 1.00 14.23 0.934 2.83 0.32 0.42 0.17 404 0.17 0.44 0.65 15.29 0.219 0.94 0.09 0.20 0.18 405 0.19 0.54 0.56 16.25 0.678 0.26 0.89 0.34 0.16 406 0.15 0.21 0.57 8.35 0.646 1.85 0.10 0.27 0.21 407 0.14 0.51 0.57 9.18 0.465 0.25 0.99 0.14 0.03 408 0.11 0.52 0.82 16.50 0.964 3.17 0.46 0.13 0.08 409 0.02 0.12 0.80 15.18 0.984 3.45 0.30 0.39 0.18 410 0.25 0.73 0.75 9.38 0.845 2.16 0.85 0.37 0.07 411 0.19 0.67 0.98 16.87 0.910 0.50 0.48 0.46 0.06 412 0.20 0.59 0.53 15.88 0.010 2.85 0.99 0.10 0.23 413 0.26 0.76 0.48 17.11 0.459 2.03 0.74 0.19 0.19 414 0.01 0.66 0.29 12.13 0.611 0.83 0.07 0.16 0.25 415 0.14 0.53 0.24 5.06 0.293 0.33 0.76 0.17 0.13 416 0.02 0.27 0.98 13.47 0.848 1.67 0.22 0.38 0.16 417 0.18 0.52 0.80 15.67 0.112 2.64 0.24 0.47 0.17 418 0.29 0.37 0.36 16.09 0.914 2.72 0.67 0.37 0.01 419 0.15 0.09 0.73 12.59 0.107 1.37 0.36 0.48 0.12 420 0.29 0.33 0.98 15.88 0.997 1.30 0.61 0.23 0.09 421 0.24 0.57 0.57 17.53 0.946 2.01 0.29 0.02 0.02 422 0.08 0.67 0.58 15.17 0.280 1.30 0.23 0.03 0.21 423 0.21 0.13 0.47 13.45 0.340 1.95 0.25 0.18 0.15 424 0.14 0.38 0.51 16.45 0.446 3.35 0.19 0.37 0.04 425 0.12 0.50 0.57 9.23 0.450 1.73 0.88 0.05 0.09 426 0.10 0.76 0.53 15.66 0.189 3.11 0.69 0.11 0.12 427 0.17 0.25 0.64 14.01 0.981 0.37 0.42 0.47 0.10 428 0.15 0.41 0.38 15.19 0.190 1.23 0.92 0.32 0.24 429 0.27 0.32 0.42 10.62 0.630 1.82 0.53 0.31 0.13 430 0.06 0.65 0.22 11.12 0.646 3.26 0.58 0.12 0.10 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 401 1.848 1.455 1.334 - - - 0.74 402 1.406 0.521 1.130 - - - 0.37 403 - - - 0.647 - - 1.41 404 - - - 1.144 - - 1.76 405 - - - 0.462 - - 0.23 406 - - - 0.253 - - 1.01 407 - - - 1.189 - - 1.12 408 - - - 1.944 - - 0.25 409 0.479 - - 0.181 - - 0.82 410 0.577 - - 1.580 - - 0.72 411 1.898 - - 0.818 - - 1.47 412 1.113 - - 1.575 - - 1.88 413 1.885 - - 1.512 - - 0.73 414 1.884 - - 0.287 - - 0.43 415 - 0.946 - 0.587 - - 1.60 416 - 1.300 - 1.065 - - 1.22 417 - 0.795 - 0.427 - - 0.82 418 - 1.075 - 0.310 - - 1.90 419 - 0.840 - 1.414 - - 1.46 420 - 1.756 - 0.398 - - 1.89 421 - - 1.768 1.928 - - 0.22 422 - - 1.066 1.688 - - 0.64 423 - - 1.890 1.344 - - 1.95 424 - - 1.902 0.556 - - 0.27 425 - - 0.821 1.035 - - 0.71 426 - - 0.277 1.420 - - 0.25 427 - 1.683 1.936 1.383 - - 1.31 428 - 0.951 0.485 1.593 - - 0.90 429 - 1.417 0.591 1.732 - - 1.40 430 - 0.760 1.950 0.497 - - 1.66 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M % 401 0.0047 0.003 0.006 7 134 45 402 0.0234 0.007 0.014 5 142 38 403 0.0112 0.003 0.008 4 132 16 404 0.0230 0.003 0.015 1 133 17 405 0.0238 0.002 0.013 4 146 18 406 0.0240 0.002 0.007 3 149 11 407 0.0035 0.002 0.005 1 171 16 408 0.0169 0.009 0.003 4 139 20 409 0.0151 0.005 0.008 4 130 18 410 0.0074 0.009 0.007 2 173 22 411 0.0195 0.008 0.016 2 145 26 412 0.0163 0.003 0.012 6 173 27 413 0.0078 0.008 0.003 2 136 40 414 0.0039 0.007 0.012 7 162 22 415 0.0149 0.002 0.010 1 177 26 416 0.0208 0.007 0.002 2 160 30 417 0.0018 0.002 0.005 0 139 14 418 0.0127 0.002 0.004 2 166 18 419 0.0190 0.003 0.018 4 169 22 420 0.0153 0.008 0.003 0 151 25 421 0.0121 0.004 0.015 4 139 42 422 0.0043 0.006 0.011 3 161 27 423 0.0018 0.002 0.009 4 146 36 424 0.0149 0.004 0.005 2 169 24 425 0.0240 0.003 0.014 3 161 26 426 0.0085 0.004 0.005 6 172 26 427 0.0089 0.003 0.004 2 131 52 428 0.0201 0.002 0.007 4 141 34 429 0.0222 0.005 0.002 5 179 37 430 0.0257 0.005 0.014 6 173 32 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 431 0.19 0.08 0.86 8.06 0.572 3.36 0.41 0.15 0.10 432 0.03 0.05 0.59 12.20 0.236 1.55 0.84 0.09 0.22 433 0.26 0.44 0.51 8.61 0.483 2.27 0.72 0.33 0.05 434 0.11 0.72 0.85 14.45 0.648 1.68 0.40 0.31 0.03 435 0.11 0.38 0.71 8.35 0.574 2.56 0.70 0.20 0.14 436 0.21 0.46 0.75 7.52 0.092 1.03 0.45 0.15 0.20 437 0.22 0.44 0.43 16.23 0.519 3.12 0.97 0.34 0.18 438 0.24 0.58 0.82 12.89 0.711 1.74 0.65 0.43 0.04 439 0.08 0.38 0.60 8.48 0.502 1.28 0.28 0.35 0.10 440 0.26 0.46 0.44 7.36 0.227 2.87 0.70 0.02 0.08 441 0.16 0.72 0.99 13.74 0.713 1.00 0.28 0.09 0.06 442 0.03 0.63 0.53 6.15 0.813 3.39 0.81 0.24 0.24 443 0.10 0.46 0.54 8.40 0.850 2.87 0.17 0.13 0.10 444 0.04 0.46 0.86 11.81 0.661 2.22 0.16 0.44 0.09 445 0.23 0.50 0.99 14.35 0.090 0.90 0.62 0.33 0.15 446 0.04 0.08 0.78 13.83 0.463 1.66 0.40 0.46 0.03 447 0.17 0.23 0.90 14.57 0.618 2.32 0.82 0.27 0.02 448 0.26 0.05 0.83 8.08 0.402 0.70 0.27 0.17 0.23 449 0.27 0.57 0.83 11.65 0.143 1.18 1.00 0.31 0.23 450 0.29 0.50 0.77 16.57 0.669 1.59 0.42 0.38 0.25 451 0.29 0.10 0.52 7.82 0.828 1.38 0.82 0.29 0.23 452 0.21 0.03 0.34 15.62 0.446 1.63 0.56 0.21 0.14 453 0.29 0.54 0.52 5.58 0.371 1.86 0.46 0.30 0.06 454 0.05 0.72 0.90 14.33 0.928 3.14 0.86 0.48 0.06 455 0.18 0.45 0.57 13.87 0.463 3.28 0.12 0.19 0.24 456 0.17 0.39 0.60 15.03 0.303 3.39 0.54 0.31 0.19 457 0.15 0.79 0.84 9.06 0.777 1.26 0.46 0.28 0.22 458 0.19 0.34 0.37 7.00 0.239 2.98 0.24 0.27 0.07 459 0.26 0.11 0.27 6.71 0.517 1.40 0.70 0.19 0.05 460 0.30 0.74 0.79 12.50 0.448 0.94 0.68 0.22 0.24 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 431 - 0.639 1.211 0.524 - - 1.34 432 - 0.726 0.049 0.494 - - 1.06 433 0.765 - 1.131 1.079 - - 0.54 434 1.520 - 1.120 0.937 - - 1.25 435 1.628 - 1.707 0.763 - - 0.21 436 1.741 - 0.571 0.229 - - 0.75 437 0.521 - 0.369 0.994 - - 1.65 438 0.678 - 1.778 0.745 - - 1.73 439 1.855 1.633 - 0.136 - - 1.57 440 1.728 1.576 - 0.842 - - 1.78 441 0.993 1.759 - 0.519 - - 1.17 442 0.294 1.893 - 1.869 - - 1.25 443 0.312 1.621 - 0.568 - - 1.72 444 0.709 0.615 - 0.247 - - 1.40 445 0.170 1.548 1.008 1.616 - - 0.86 446 1.375 1.100 0.448 1.332 - - 0.75 447 1.970 1.952 0.558 0.087 - - 1.64 448 0.671 1.758 1.983 1.521 - - 1.45 449 0.094 0.199 1.411 1.326 - - 0.77 450 0.950 1.927 0.503 0.154 - - 0.22 451 0.901 - - - 4.33 - 0.42 452 0.608 - - - 2.63 - 1.03 453 0.758 - - - 1.95 - 0.89 454 0.010 - - - 3.93 - 1.50 455 1.046 - - - 0.49 - 0.74 456 1.534 - - - 0.53 - 1.06 457 - 0.062 - - 0.83 - 0.33 458 - 1.419 - - 3.00 - 1.86 459 - 1.131 - - 3.86 - 0.85 460 - 1.846 - - 4.98 - 1.52 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 431 0.0101 0.006 0.012 0 176 32 432 0.0157 0.006 0.001 3 166 22 433 0.0226 0.003 0.008 2 144 32 434 0.0108 0.005 0.020 2 140 37 435 0.0053 0.002 0.014 3 131 40 436 0.0165 0.006 0.006 4 144 33 437 0.0242 0.010 0.013 6 132 23 438 0.0088 0.009 0.012 2 172 38 439 0.0099 0.005 0.009 3 169 33 440 0.0078 0.002 0.002 6 149 36 441 0.0124 0.003 0.007 5 141 31 442 0.0190 0.006 0.010 1 171 36 443 0.0226 0.001 0.017 3 167 28 444 0.0036 0.009 0.009 1 159 23 445 0.0015 0.010 0.008 6 172 41 446 0.0268 0.002 0.013 4 135 37 447 0.0146 0.004 0.010 1 150 47 448 0.0197 0.007 0.006 6 170 52 449 0.0074 0.007 0.017 3 174 31 450 0.0176 0.006 0.003 6 138 33 451 0.0007 0.008 0.006 3 141 15 452 0.0114 0.002 0.005 0 135 18 453 0.0149 0.009 0.016 3 173 13 454 0.0214 0.009 0.017 3 133 11 455 0.0107 0.002 0.005 3 142 18 456 0.0084 0.007 0.005 5 178 26 457 0.0091 0.002 0.004 5 144 11 458 0.0229 0.002 0.010 5 143 24 459 0.0152 0.002 0.008 7 152 16 460 0.0107 0.004 0.006 3 149 25 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C S i Mn C r M o W V Nb N 461 0.27 0.54 0.21 15.79 0.868 2.70 0.03 0.01 0.01 462 0.13 0.55 0.80 7.85 0.113 1.18 0.06 0.24 0.15 463 0.25 0.26 0.41 6.09 0.014 0.77 0.11 0.07 0.03 464 0.30 0.30 0.93 14.73 0.397 2.59 0.51 0.18 0.19 465 0.23 0.57 0.62 12.45 0.620 2.82 0.12 0.47 0.14 466 0.14 0.54 0.55 9.95 0.021 2.57 0.27 0.13 0.18 467 0.28 0.09 0.59 11.56 0.409 2.93 0.28 0.31 0.16 468 0.01 0.24 0.60 15.14 0.641 3.35 0.99 0.43 0.03 469 0.02 0.49 0.46 5.65 0.550 1.67 0.27 0.18 0.25 470 0.25 0.72 0.44 13.48 0.473 0.64 0.90 0.20 0.04 471 0.08 0.78 0.80 16.87 0.738 1.34 0.26 0.17 0.21 472 0.18 0.56 0.61 13.71 0.186 3.25 0.66 0.26 0.24 473 0.22 0.70 0.94 14.90 0.146 0.85 0.45 0.37 0.10 474 0.29 0.68 0.86 5.26 0.960 1.91 0.95 0.44 0.21 475 0.06 0.38 0.23 15.27 0.969 2.54 0.04 0.39 0.19 476 0.21 0.47 0.55 10.34 0.013 0.58 0.98 0.13 0.11 477 0.25 0.40 0.86 14.23 0.918 0.44 0.69 0.07 0.05 478 0.13 0.05 0.62 11.72 0.517 3.18 0.94 0.14 0.10 479 0.11 0.48 0.53 7.37 0.157 1.72 0.13 0.49 0.21 480 0.26 0.38 0.84 5.44 0.166 0.43 0.52 0.07 0.11 481 0.12 0.79 0.22 10.31 0.878 0.43 0.50 0.26 0.11 482 0.07 0.41 0.55 13.34 0.637 2.82 0.39 0.26 0.18 483 0.20 0.28 0.47 5.80 0.764 2.09 0.51 0.22 0.03 484 0.04 0.29 0.28 11.76 0.117 1.05 0.72 0.06 0.24 485 0.12 0.28 0.63 15.93 0.014 2.40 0.84 0.20 0.15 486 0.09 0.55 0.60 9.73 0.294 0.71 0.23 0.31 0.09 487 0.06 0.55 0.85 10.58 0.799 0.36 0.21 0.06 0.14 488 0.27 0.57 0.85 9.79 0.363 0.78 0.58 0.10 0.02 489 0.23 0.06 0.87 11.59 0.812 1.47 0.74 0.12 0.17 490 0.05 0.09 0.39 7.64 0.499 0.22 0.49 0.04 0.07 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 461 - 0.284 - - 0.84 - 0.86 462 - 0.053 - - 2.56 - 0.37 463 1.029 0.881 - - 2.28 - 1.59 464 0.305 0.413 - - 3.94 - 1.50 465 0.086 1.331 - - 1.93 - 0.68 466 1.035 0.284 - - 0.30 - 1.57 467 1.834 1.978 - - 0.66 - 0.27 468 1.127 0.071 - - 2.23 - 1.89 469 - - 1.350 - 1.78 - 1.60 470 - - 1.931 - 0.92 - 1.83 471 - - 0.305 - 3.74 - 0.51 472 - - 1.140 - 2.19 - 0.89 473 - - 1.093 - 2.73 - 1.83 474 - - 0.834 - 4.53 - 1.19 475 1.094 - 0.052 - 1.99 - 0.49 476 1.700 - 1.388 - 3.94 - 0.33 477 0.871 - 1.545 - 2.39 - 0.43 478 0.274 - 1.194 - 3.81 - 0.50 479 0.595 - 1.995 - 4.95 - 0.23 480 0.478 - 0.636 - 2.62 - 0.21 481 - 1.988 1.762 - 0.90 - 1.08 482 - 1.189 0.072 - 3.74 - 1.62 483 - 0.864 0.220 - 0.76 - 0.65 484 - 1.683 0.881 - 3.17 - 1.45 485 - 0.327 0.723 - 2.97 - 1.04 486 - 0.457 1.435 - 1.82 - 1.83 487 0.262 1.739 1.663 - 3.70 - 1.72 488 0.936 0.868 0.105 - 3.02 - 0.41 489 1.241 0.503 0.415 - 1.41 - 0.31 490 0.844 1.313 1.270 - 0.44 - 0.22 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 461 0.0195 0.003 0.019 3 162 9 462 0.0220 0.002 0.007 1 144 13 463 0.0282 0.004 0.014 4 147 26 464 0.0182 0.007 0.017 1 149 12 465 0.0165 0.005 0.004 6 177 23 466 0.0189 0.001 0.001 3 161 19 467 0.0202 0.004 0.014 3 176 41 468 0.0008 0.001 0.010 5 151 17 469 0.0150 0.006 0.016 6 165 22 470 0.0282 0.004 0.019 6 143 28 471 0.0061 0.005 0.007 2 139 16 472 0.0182 0.006 0.014 3 132 23 473 0.0148 0.003 0.008 4 173 23 474 0.0206 0.009 0.006 4 141 17 475 0.0160 0.009 0.013 2 162 16 476 0.0260 0.002 0.018 4 166 34 477 0.0157 0.009 0.007 1 154 24 478 0.0105 0.009 0.016 3 154 21 479 0.0050 0.002 0.004 6 170 26 480 0.0243 0.009 0.014 4 178 20 481 0.0040 0.005 0.015 1 157 40 482 0.0286 0.008 0.005 5 158 21 483 0.0185 0.002 0.008 4 161 15 484 0.0136 0.003 0.011 2 168 32 485 0.0089 0.006 0.012 3 156 14 486 0.0147 0.005 0.008 4 153 25 487 0.0110 0.008 0.015 7 137 41 488 0.0228 0.003 0.009 3 136 23 489 0.0152 0.003 0.008 1 177 30 490 0.0283 0.002 0.008 5 164 38 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 491 0.11 0.52 0.86 8.60 0.255 3.11 0.18 0.26 0.04 492 0.22 0.44 0.96 12.39 0.406 1.30 0.62 0.45 0.05 493 0.18 0.12 0.55 10.29 0.285 2.52 0.68 0.29 0.05 494 0.10 0.59 0.71 6.80 0.746 2.96 0.68 0.19 0.24 495 0.06 0.18 0.91 12.91 0.623 2.06 0.46 0.32 0.23 496 0.03 0.70 0.61 6.71 0.744 0.94 0.84 0.36 0.09 497 0.11 0.46 0.87 12.13 0.441 0.67 0.19 0.45 0.03 498 0.23 0.12 0.39 14.14 0.553 0.73 0.30 0.04 0.13 499 0.21 0.32 0.99 16.95 0.917 0.58 0.53 0.26 0.10 500 0.15 0.16 0.59 12.09 0.371 1.32 0.72 0.07 0.15 501 0.15 0.30 0.63 16.91 0.259 0.80 0.22 0.36 0.24 502 0.16 0.21 0.58 16.24 0.900 3.39 0.34 0.06 0.08 503 0.12 0.16 0.33 14.50 0.146 0.29 0.41 0.32 0.25 504 0.29 0.79 0.51 9.34 0.813 2.54 0.78 0.09 0.21 505 0.18 0.03 0.63 5.44 0.262 2.99 0.32 0.02 0.06 506 0.18 0.10 0.94 13.51 0.811 2.75 0.80 0.02 0.11 507 0.09 0.48 0.90 11.93 0.804 2.91 0.60 0.01 0.21 508 0.01 0.64 0.39 17.95 0.566 1.27 0.05 0.17 0.18 509 0.05 0.45 0.88 16.71 0.448 2.28 0.46 0.40 0.12 510 0.14 0.58 0.23 5.75 0.275 0.41 0.70 0.15 0.22 511 0.11 0.50 0.72 15.75 0.393 1.77 0.11 0.07 0.08 512 0.04 0.48 0.22 11.89 0.129 2.46 0.97 0.30 0.15 513 0.18 0.77 0.98 11.56 0.319 0.32 0.19 0.06 0.03 514 0.19 0.08 0.88 6.15 0.302 3.04 0.05 0.47 0.03 515 0.03 0.62 0.98 12.92 0.405 1.82 0.88 0.23 0.24 516 0.08 0.70 0.38 10.44 0.978 1.11 0.09 0.25 0.14 517 0.29 0.58 0.91 9.47 0.854 0.35 0.43 0.44 0.17 518 0.04 0.53 0.45 7.77 0.857 2.25 0.29 0.23 0.04 519 0.29 0.42 0.48 16.33 0.833 3.04 0.97 0.02 0.08 520 0.13 0.50 0.46 13.55 0.621 0.51 0.84 0.49 0.14 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 491 1.420 0.968 1.336 - 1.78 - 0.74 492 1.612 0.146 0.286 - 4.58 - 1.59 493 - - - 1.815 0.92 - 0.66 494 - - - 0.475 1.99 - 0.36 495 - - - 1.386 2.13 - 1.29 496 - - - 0.238 3.04 - 1.37 497 - - - 0.718 1.53 - 0.29 498 - - - 1.476 1.57 - 1.37 499 1.378 - - 1.204 4.81 - 0.69 500 1.877 - - 1.555 0.83 - 0.68 501 1.073 - - 0.228 0.89 - 1.03 502 0.634 - - 0.848 1.70 - 1.45 503 1.207 - - 1.123 2.60 - 0.74 504 0.492 - - 0.742 2.77 - 0.42 505 - 0.599 - 0.337 1.40 - 1.09 506 - 1.634 - 0.592 4.87 - 0.64 507 - 1.272 - 1.196 2.87 - 0.58 508 - 1.182 - 0.802 4.15 - 1.53 509 - 1.043 - 0.094 0.75 - 1.38 510 - 1.511 - 1.722 3.86 - 1.63 511 - - 1.968 0.357 0.65 - 1.08 512 - - 1.807 0.712 4.83 - 1.25 513 - - 0.631 0.404 1.12 - 1.83 514 - - 1.130 1.153 0.84 - 1.65 515 - - 1.970 0.608 3.14 - 0.41 516 - - 0.844 0.450 2.44 - 0.48 517 - 1.406 1.361 1.320 0.29 - 1.60 518 - 1.987 0.280 1.939 3.22 - 0.77 519 - 1.217 1.199 1.948 0.76 - 1.29 520 - 0.797 1.829 1.029 4.15 - 1.04 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 491 0.0123 0.002 0.006 3 173 39 492 0.0071 0.003 0.008 7 157 21 493 0.0079 0.003 0.012 2 146 24 494 0.0245 0.006 0.004 5 165 15 495 0.0223 0.003 0.010 3 143 16 496 0.0113 0.005 0.008 0 157 8 497 0.0017 0.009 0.014 5 136 16 498 0.0032 0.008 0.005 2 156 25 499 0.0261 0.002 0.008 1 147 30 500 0.0208 0.003 0.009 4 135 38 501 0.0119 0.009 0.005 7 148 25 502 0.0095 0.009 0.003 4 164 19 503 0.0092 0.003 0.018 6 160 25 504 0.0205 0.002 0.020 4 165 18 505 0.0240 0.005 0.014 4 131 15 506 0.0143 0.010 0.016 5 136 26 507 0.0018 0.007 0.014 6 133 24 508 0.0262 0.007 0.013 1 149 25 509 0.0082 0.010 0.002 1 162 23 510 0.0021 0.004 0.006 1 150 38 511 0.0033 0.003 0.012 6 140 32 512 0.0220 0.004 0.017 1 136 30 513 0.0080 0.006 0.018 4 164 17 514 0.0020 0.002 0.002 5 153 23 515 0.0135 0.001 0.014 7 131 34 516 0.0224 0.001 0.003 1 175 22 517 0.0097 0.006 0.013 5 163 39 518 0.0295 0.003 0.013 3 148 41 519 0.0026 0.002 0.019 1 157 39 520 0.0285 0.005 0.008 1 143 41 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 521 0.09 0.67 0.26 16.70 0.548 2.34 0.72 0.07 0.04 522 0.11 0.77 0.96 17.31 0.463 3.08 0.45 0.16 0.24 523 0.17 0.31 0.41 13.03 0.187 2.15 0.85 0.42 0.09 524 0.05 0.31 0.89 8.43 0.069 0.70 0.29 0.29 0.15 525 0.15 0.26 0.27 14.18 0.923 3.06 0.07 0.18 0.02 526 0.28 0.42 0.41 15.26 0.613 0.54 0.05 0.02 0.03 527 0.24 0.67 0.78 16.12 0.466 2.46 0.05 0.44 0.25 528 0.13 0.49 0.86 14.48 0.808 3.32 0.90 0.16 0.17 529 0.20 0.53 0.92 14.76 0.484 0.91 0.47 0.30 0.22 530 0.10 0.27 0.41 14.93 0.335 1.34 0.08 0.06 0.01 531 0.22 0.75 0.81 12.70 0.682 0.72 0.05 0.10 0.10 532 0.08 0.68 0.39 12.54 0.873 3.49 0.72 0.33 0.09 533 0.08 0.31 0.22 5.73 0.240 0.83 0.44 0.17 0.17 534 0.29 0.69 0.55 16.06 0.103 0.43 0.53 0.29 0.07 535 0.25 0.13 0.87 9.12 0.824 1.81 0.83 0.12 0.11 536 0.20 0.46 0.25 15.12 0.223 2.73 0.20 0.30 0.13 537 0.08 0.36 0.94 12.48 0.146 1.04 0.93 0.03 0.21 538 0.28 0.12 0.83 12.06 0.418 1.13 0.41 0.45 0.20 539 0.04 0.77 0.98 11.84 0.884 2.45 0.43 0.25 0.16 530 0.03 0.22 0.84 15.87 0.871 1.14 0.84 0.09 0.19 541 0.06 0.31 0.71 15.93 0.728 1.65 0.98 0.13 0.24 542 0.22 0.52 0.84 16.03 0.282 1.77 0.70 0.05 0.16 543 0.18 0.32 0.31 7.84 0.873 0.98 0.33 0.25 0.14 544 0.03 0.37 0.58 14.93 0.328 0.32 0.18 0.41 0.14 545 0.01 0.15 0.32 9.32 0.984 2.62 0.10 0.22 0.01 546 0.09 0.71 0.60 15.01 0.200 0.74 0.93 0.31 0.19 547 0.07 0.74 0.49 16.69 0.784 0.70 0.02 0.37 0.15 548 0.04 0.52 0.26 12.21 0.582 1.96 0.18 0.31 0.22 549 0.24 0.67 0.57 12.50 0.928 0.69 0.75 0.06 0.12 550 0.20 0.70 0.90 8.91 0.161 2.94 0.09 0.02 0.17 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 521 - 1.365 0.836 0.848 2.98 - 0.67 522 - 1.611 0.870 0.066 3.68 - 0.75 523 1.828 - 0.653 1.394 3.12 - 1.91 524 0.234 - 1.815 1.474 0.44 - 1.14 525 1.435 - 0.036 1.973 4.44 - 1.74 526 0.149 - 0.984 1.575 4.77 - 1.64 527 0.015 - 1.338 0.941 0.62 - 0.50 528 0.706 - 1.753 0.750 0.81 - 1.65 529 0.888 1.824 - 1.679 4.58 - 0.31 530 1.249 0.694 - 0.401 1.52 - 0.67 531 0.462 1.294 - 0.588 2.86 - 1.52 532 0.187 1.268 - 1.879 2.94 - 1.69 533 0.075 1.335 - 1.002 3.49 - 0.89 534 0.827 0.153 - 0.607 1.28 - 0.60 535 0.120 0.372 1.380 1.348 2.68 - 1.44 536 0.595 0.675 0.614 0.903 2.09 - 1.29 537 0.960 1.725 0.976 0.955 3.62 - 0.79 538 1.869 0.194 0.113 1.146 1.54 - 0.51 539 1.982 1.779 0.737 0.198 2.41 - 1.98 530 2.000 0.144 1.500 1.749 2.97 - 1.31 541 0.566 - - - - 2.44 0.88 542 0.386 - - - - 4.35 1.31 543 1.093 - - - - 2.05 0.50 544 1.369 - - - - 2.00 0.86 545 1.909 - - - - 3.39 1.19 546 1.372 - - - - 3.02 1.18 547 - 0.694 - - - 4.87 1.45 548 - 1.400 - - - 3.45 0.82 549 - 0.936 - - - 0.29 0.76 550 - 0.968 - - - 1.88 1.02 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 521 0.0127 0.001 0.016 3 134 34 522 0.0249 0.008 0.001 4 157 26 523 0.0009 0.009 0.008 0 142 38 524 0.0100 0.009 0.015 1 163 36 525 0.0025 0.005 0.018 6 151 39 526 0.0036 0.006 0.005 2 158 31 527 0.0229 0.005 0.010 4 161 25 528 0.0112 0.005 0.013 1 138 35 529 0.0084 0.005 0.018 1 166 46 530 0.0243 0.003 0.014 3 175 30 531 0.0091 0.003 0.016 1 165 31 532 0.0029 0.002 0.002 1 165 37 533 0.0011 0.005 0.017 3 178 26 534 0.0282 0.004 0.010 1 131 19 535 0.0048 0.008 0.006 2 153 34 536 0.0004 0.005 0.012 4 170 34 537 0.0252 0.004 0.005 7 162 45 538 0.0297 0.004 0.002 1 154 38 539 0.0090 0.006 0.009 4 175 43 530 0.0118 0.005 0.003 4 154 54 541 0.0063 0.004 0.001 3 167 11 542 0.0146 0.006 0.009 3 142 16 543 0.0225 0.001 0.015 4 157 20 544 0.0106 0.005 0.014 3 140 20 545 0.0037 0.003 0.015 5 169 26 546 0.0266 0.003 0.013 6 146 25 547 0.0297 0.008 0.015 4 148 17 548 0.0233 0.002 0.017 6 180 21 549 0.0022 0.007 0.008 2 168 13 550 0.0067 0.008 0.003 4 165 21 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 551 0.16 0.47 0.70 5.73 0.609 1.57 0.50 0.36 0.21 552 0.06 0.25 0.67 14.06 0.626 1.03 0.35 0.26 0.08 553 0.01 0.68 0.65 12.02 0.032 0.72 0.45 0.13 0.21 554 0.25 0.48 0.93 10.68 0.669 3.45 0.65 0.14 0.22 555 0.15 0.67 0.56 7.65 0.862 2.01 0.29 0.46 0.07 556 0.10 0.36 0.22 7.62 0.968 0.89 0.68 0.26 0.18 557 0.19 0.59 0.98 8.28 0.317 2.81 0.21 0.45 0.05 558 0.24 0.06 0.71 14.01 0.235 2.28 0.16 0.46 0.23 559 0.05 0.58 0.86 16.07 0.052 2.00 0.37 0.43 0.21 560 0.15 0.08 0.92 5.99 0.622 1.56 0.22 0.32 0.06 561 0.21 0.39 0.35 14.08 0.772 0.31 0.99 0.03 0.11 562 0.17 0.21 0.62 12.26 0.843 2.71 0.58 0.21 0.07 563 0.15 0.18 0.40 11.34 0.171 1.60 0.28 0.29 0.03 564 0.22 0.58 0.76 15.69 0.086 1.39 0.43 0.44 0.07 565 0.06 0.10 0.77 16.73 0.427 3.20 0.87 0.34 0.15 566 0.06 0.56 0.29 12.23 0.028 3.16 0.45 0.39 0.23 567 0.30 0.28 0.40 6.64 0.228 2.42 0.48 0.02 0.14 568 0.16 0.68 0.95 17.20 0.850 2.03 0.81 0.13 0.10 569 0.04 0.48 0.63 15.87 0.745 1.48 0.29 0.15 0.17 570 0.16 0.69 0.49 6.96 0.736 0.20 0.22 0.49 0.09 571 0.06 0.05 0.41 14.39 0.179 2.68 0.47 0.10 0.17 572 0.26 0.75 0.66 16.58 0.888 3.35 0.36 0.35 0.13 573 0.13 0.73 0.71 11.34 0.224 1.72 0.73 0.20 0.18 574 0.21 0.62 0.42 16.10 0.006 0.53 0.42 0.04 0.03 575 0.16 0.31 0.48 15.72 0.075 0.90 0.27 0.06 0.12 576 0.23 0.05 0.72 7.87 0.252 2.23 0.10 0.39 0.06 577 0.06 0.10 0.24 16.61 0.389 0.74 0.74 0.24 0.04 578 0.06 0.35 0.91 7.32 0.818 2.47 0.55 0.26 0.16 579 0.03 0.65 0.57 10.25 0.876 1.92 0.85 0.37 0.23 580 0.21 0.11 0.72 10.38 0.409 1.88 0.99 0.48 0.12 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 551 - 1.163 - - - 2.58 1.27 552 - 0.203 - - - 4.02 0.33 553 0.758 1.720 - - - 0.52 0.57 554 1.744 1.419 - - - 1.01 1.73 555 0.717 1.982 - - - 2.27 0.83 556 1.334 0.065 - - - 1.11 0.23 557 0.274 1.342 - - - 3.95 1.47 558 0.186 1.479 - - - 2.80 0.65 559 - - 0.968 - - 1.65 1.95 560 - - 0.609 - - 4.54 1.50 561 - - 0.498 - - 3.47 0.78 562 - - 1.290 - - 4.81 0.42 563 - - 1.690 - - 3.06 1.92 564 - - 1.357 - - 4.57 1.37 565 1.501 - 1.926 - - 1.35 1.18 566 1.464 - 0.140 - - 4.65 1.97 567 1.448 - 1.617 - - 4.04 1.62 568 0.145 - 0.046 - - 1.21 1.67 569 0.196 - 1.116 - - 4.89 0.89 570 0.293 - 1.467 - - 4.74 0.80 571 - 1.772 0.787 - - 4.76 0.21 572 - 0.587 1.743 - - 1.72 1.49 573 - 0.327 1.014 - - 4.49 1.70 574 - 1.695 1.273 - - 0.28 1.41 575 - 0.357 0.190 - - 0.28 0.34 576 - 1.963 0.423 - - 3.72 1.78 577 0.748 0.217 1.659 - - 4.99 1.84 578 1.401 0.776 1.577 - - 3.29 1.12 579 0.159 1.287 1.805 - - 2.67 0.22 580 0.669 1.461 1.073 - - 4.73 0.67 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 551 0.0015 0.008 0.008 5 148 17 552 0.0267 0.004 0.002 6 172 8 553 0.0026 0.006 0.019 6 163 32 554 0.0141 0.007 0.008 4 174 29 555 0.0117 0.005 0.015 3 133 27 556 0.0051 0.003 0.016 1 143 23 557 0.0043 0.010 0.009 5 131 18 558 0.0048 0.009 0.020 2 175 22 559 0.0162 0.009 0.015 6 177 18 560 0.0189 0.003 0.003 4 167 19 561 0.0078 0.004 0.008 7 145 9 562 0.0080 0.006 0.018 2 141 16 563 0.0296 0.006 0.010 2 131 23 564 0.0226 0.009 0.019 7 144 20 565 0.0272 0.003 0.014 4 131 35 566 0.0237 0.005 0.002 3 147 17 567 0.0067 0.005 0.017 6 144 35 568 0.0019 0.006 0.017 2 174 8 569 0.0037 0.006 0.020 3 165 22 570 0.0074 0.004 0.002 2 144 25 571 0.0084 0.002 0.018 1 141 29 572 0.0012 0.005 0.007 1 132 25 573 0.0263 0.005 0.014 6 145 24 574 0.0189 0.001 0.017 7 157 28 575 0.0038 0.006 0.012 6 148 18 576 0.0061 0.009 0.016 3 168 31 577 0.0210 0.008 0.007 4 171 29 578 0.0134 0.006 0.019 6 136 36 579 0.0085 0.003 0.010 6 138 39 580 0.0162 0.009 0.008 2 157 33 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 581 0.26 0.15 0.42 5.47 0.232 1.78 0.31 0.04 0.01 582 0.29 0.27 0.73 13.00 0.693 1.08 0.61 0.17 0.24 583 0.09 0.31 0.32 17.77 0.126 0.89 0.75 0.31 0.15 584 0.06 0.56 0.27 11.16 0.864 2.33 0.09 0.39 0.19 585 0.29 0.49 0.83 10.43 0.250 3.19 0.90 0.07 0.08 586 0.02 0.37 0.69 7.15 0.614 1.28 0.10 0.25 0.15 587 0.06 0.06 0.51 12.08 0.794 1.05 0.95 0.13 0.22 588 0.07 0.60 0.94 16.45 0.616 0.23 0.82 0.34 0.15 589 0.16 0.71 0.68 11.92 0.437 3.29 0.07 0.34 0.02 590 0.13 0.26 0.78 15.66 0.573 3.08 0.49 0.02 0.01 591 0.22 0.66 0.32 6.08 0.875 2.37 0.45 0.06 0.10 592 0.10 0.64 0.77 7.16 0.181 2.24 0.76 0.11 0.25 593 0.29 0.44 0.38 16.55 0.306 0.50 0.28 0.36 0.17 594 0.18 0.73 0.63 6.24 0.100 3.23 0.82 0.46 0.07 595 0.29 0.20 0.59 6.57 0.893 1.61 0.74 0.10 0.14 596 0.28 0.66 0.92 8.93 0.029 1.71 0.86 0.43 0.24 597 0.26 0.45 0.31 11.18 0.341 1.35 0.53 0.37 0.07 598 0.17 0.21 0.20 17.68 0.164 3.28 0.08 0.10 0.08 599 0.26 0.19 0.49 13.31 0.331 2.03 0.34 0.27 0.23 600 0.19 0.-29 0.22 15.47 0.684 1.99 0.16 0.06 0.24 601 0.06 0.75 0.48 9.00 0.559 2.61 0.35 0.38 0.07 602 0.25 0.27 0.73 11.25 0.289 1.71 0.27 0.41 0.04 603 0.14 0.69 0.84 13.59 0.208 0.40 0.25 0.31 0.23 604 0.26 0.69 0.67 7.38 0.652 3.06 0.12 0.24 0.13 605 0.27 0.55 0.90 10.01 0.958 0.96 0.71 0.39 0.17 606 0.13 0.52 1.00 12.72 0.456 3.36 0.86 0.15 0.07 607 0.07 0.48 0.42 13.60 0.998 1.58 0.93 0.22 0.16 608 0.20 0.69 0.66 16.91 0.910 1.62 0.25 0.23 0.04 609 0.03 0.63 0.76 14.01 0.526 1.29 0.13 0.14 0.02 610 0.24 0.57 0.20 9.22 0.685 3.35 0.90 0.33 0.18 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 581 1.622 1.938 0.020 - - 1.45 0.35 582 0.687 1.423 1.327 - - 1.73 1.69 583 - - - 1.260 - 4.65 1.65 584 - - - 1.256 - 2.37 0.89 585 - - - 1.984 - 1.20 1.78 586 - - - 0.122 - 2.79 0.43 587 - - - 1.345 - 3.91 1.94 588 - - - 1.320 - 1.47 0.65 589 0.546 - - 0.716 - 4.16 1.60 590 0.644 - - 0.228 - 1.69 1.86 591 1.916 - - 1.515 - 2.86 0.20 592 1.005 - - 0.252 - 2.05 0.83 593 1.589 - - 0.094 - 3.26 0.77 594 0.356 - - 1.712 - 3.31 0.59 595 - 1.529 - 1.801 - 3.84 0.92 596 - 1.422 - 0.017 - 4.03 1.45 597 - 1.391 - 0.041 - 3.13 1.90 598 - 1.101 - 1.535 - 0.31 1.97 599 - 1.223 - 1.181 - 2.05 1.38 600 - 1.421 - 0.639 - 2.66 0.69 601 - - 1.739 1.583 - 1.42 1.44 602 - - 0.303 1.700 - 2.36 1.54 603 - - 1.329 0.655 - 2.26 0.67 604 - - 0.498 0.114 - 2.76 0.37 605 - - 1.481 0.756 - 3.05 1.21 606 - - 0.943 1.241 - 2.30 1.10 607 - 0.662 0.552 1.241 - 4.57 1.55 608 - 0.723 0.986 0.437 - 4.28 1.36 609 - 0.908 1.908 1.479 - 2.98 1.14 610 - 1.901 0.016 1.085 - 2.39 1.50 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M % 581 0.0168 0.002 0.017 0 170 35 582 0.0054 0.001 0.016 3 154 38 583 0.0068 0.002 0.002 6 138 15 584 0.0015 0.006 0.019 4 149 19 585 0.0291 0.009 0.017 7 164 26 586 0.0103 0.004 0.001 2 163 9 587 0.0143 0.003 0.017 0 172 18 588 0.0221 0.004 0.013 3 169 16 589 0.0280 0.007 0.005 5 156 22 590 0.0276 0.005 0.010 7 138 19 591 0.0161 0.001 0.006 6 141 33 592 0.0032 0.008 0.017 5 142 21 593 0.0289 0.010 0.012 6 171 25 594 0.0283 0.010 0.007 6 154 30 595 0.0268 0.007 0.017 2 169 32 596 0.0193 0.003 0.003 7 144 19 597 0.0009 0.008 0.017 3 157 17 598 0.0265 0.009 0.018 6 160 28 599 0.0167 0.010 0.013 5 157 27 600 0.0257 0.009 0.018 2 149 29 601 0.0193 0.005 0.010 6 140 34 602 0.0224 0.006 0.006 5 158 25 603 0.0152 0.001 0.012 6 179 27 604 0.0076 0.007 0.015 0 132 10 605 0.0247 0.008 0.003 4 170 27 606 0.0015 0.003 0.020 2 170 25 607 0.0229 0.009 0.015 0 135 29 608 0.0095 0.010 0.014 2 143 27 609 0.0159 0.010 0.003 4 172 38 610 0.0075 0.007 0.010 4 173 33 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 611 0.06 0.75 0.85 6.96 0.221 0.67 0.93 0.24 0.13 612 0.16 0.68 0.97 5.05 0.465 0.93 0.06 0.28 0.07 613 0.20 0.61 0.85 14.50 0.765 0.34 0.09 0.13 0.20 614 0.15 0.40 0.74 13.63 0.956 3.29 0.87 0.43 0.24 615 0.24 0.73 0.92 6.76 0.871 0.98 0.26 0.38 0.03 616 0.27 0.28 0.85 11.21 0.341 1.10 0.06 0.14 0.12 617 0.07 0.10 0.80 11.88 0.697 1.47 0.61 0.36 0.01 618 0.15 0.43 0.23 6.61 0.290 3.21 0.27 0.23 0.13 619 0.18 0.40 0.63 12.80 0.940 2.46 0.84 0.15 0.20 620 0.11 0.25 0.26 15.43 0.505 0.37 0.22 0.30 0.18 621 0.19 0.25 0.58 5.71 0.799 1.30 0.18 0.10 0.04 622 0.08 0.26 0.26 7.56 0.172 1.43 0.09 0.20 0.09 623 0.17 0.16 0.78 5.84 0.449 0.22 0.76 0.29 0.06 624 0.11 0.61 0.41 11.42 0.473 0.43 0.06 0.27 0.14 625 0.16 0.69 0.60 9.18 0.081 1.51 0.79 0.07 0.06 626 0.25 0.27 0.43 9.97 0.104 2.91 0.33 0.11 0.13 627 0.21 0.79 0.58 11.66 0.378 0.82 0.96 0.29 0.20 628 0.13 0.57 0.50 12.18 0.247 1.29 0.58 0.30 0.23 629 0.10 0.63 0.47 15.79 0.038 2.10 0.96 0.05 0.17 630 0.22 0.08 0.34 7.35 0.583 2.72 0.98 0.44 0.24 631 0.02 0.34 0.81 17.28 0.726 0.96 0.48 0.17 0.14 632 0.30 0.50 0.92 10.90 0.297 2.86 0.26 0.13 0.08 633 0.01 0.45 0.95 5.68 0.645 1.34 0.67 0.50 0.15 634 0.27 0.06 0.38 5.99 0.101 2.42 0.08 0.45 0.17 635 0.16 0.75 0.27 9.63 0.992 0.62 0.77 0.15 0.12 636 0.05 0.43 0.88 7.89 0.657 0.30 0.12 0.26 0.19 637 0.05 0.56 0.89 11.77 0.438 0.98 0.44 0.20 0.22 638 0.12 0.23 0.96 6.15 0.172 2.10 0.58 0.15 0.18 639 0.20 0.07 0.97 8.23 0.674 3.08 0.36 0.25 0.02 640 0.10 0.74 0.38 9.49 0.309 3.44 0.15 0.20 0.07 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 611 - 1.381 0.967 0.900 - 1.64 0.34 612 - 0.010 0.436 1.594 - 2.40 1.87 613 1.738 - 1.064 0.821 - 3.80 1.28 614 0.015 - 0.569 1.286 - 2.72 1.88 615 0.557 - 0.610 1.656 - 0.78 0.70 616 0.062 - 1.833 1.572 - 1.89 1.89 617 1.170 - 0.944 0.755 - 0.64 0.72 618 1.575 - 0.590 1.822 - 3.24 1.33 619 1.956 0.861 - 1.500 - 1.90 0.79 620 0.979 0.857 - 1.441 - 0.52 0.56 621 0.312 1.024 - 1.287 - 3.11 0.36 622 1.631 1.064 - 0.743 - 4.11 0.79 623 0.603 0.650 - 1.475 - 2.74 0.66 G24 0.890 1.443 - 1.153 - 2.98 1.46 625 0.186 0.115 0.895 0.440 - 1.67 0.21 626 0.151 0.336 0.101 1.003 - 2.78 1.11 627 0.464 1.771 0.887 0.537 - 0.78 1.17 628 1.782 0.127 1.952 0.700 - 4.45 0.98 629 1.789 0.039 0.951 0.176 - 1.03 0.27 630 0.150 0.207 1.569 1.629 - 1.74 1.42 631 0.528 - - - 2.19 0.92 1.45 632 1.613 - - - 1.89 0.24 1.85 633 0.079 - - - 2.42 3.69 0.54 634 0.592 - - - 3.05 0.91 0.81 635 0.808 - - - 2.96 3.10 0.59 636 1.428 - - - 1.37 4.66 1.36 637 - 1.490 - - 2.29 4.81 1.02 638 - 1.763 - - 2.49 0.33 1.99 639 - 1.309 - - 3.66 2.50 1.27 640 - 1.828 - - 2.54 3.24 0.35 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 611 0.0243 0.004 0.011 6 176 35 612 0.0015 0.009 0.013 7 132 27 613 0.0087 0.007 0.012 4 170 37 614 0.0263 0.010 0.006 4 142 24 615 0.0050 0.007 0.020 6 176 28 616 0.0134 0.005 0.013 1 175 34 617 0.0031 0.009 0.019 6 166 29 618 0.0129 0.002 0.017 2 152 41 619 0.0240 0.007 0.013 3 161 37 620 0.0158 0.007 0.013 6 145 39 621 0.0137 0.006 0.015 4 133 34 622 0.0127 0.003 0.015 2 152 31 623 0.0077 0.009 0.010 4 179 29 624 0.0089 0.010 0.006 4 144 31 625 0.0112 0.008 0.019 1 172 27 626 0.0099 0.007 0.009 1 143 24 627 0.0003 0.005 0.010 2 133 42 628 0.0069 0.009 0.018 5 171 40 629 0.0251 0.010 0.013 0 133 35 630 0.0202 0.009 0.009 1 174 38 631 0.0020 0.002 0.013 5 170 10 632 0.0104 0.005 0.013 6 175 19 633 0.0109 0.007 0.005 2 166 12 634 0.0281 0.006 0.005 6 171 12 635 0.0127 0.002 0.001 2 142 19 636 0.0043 0.006 0.018 4 158 24 637 0.0130 0.008 0.005 6 171 24 638 0.0188 0.006 0.007 5 158 25 639 0.0025 0.008 0.011 6 149 17 640 0.0030 0.004 0.005 1 144 23 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 641 0.07 0.17 0.66 14.30 0.390 0.93 0.23 0.14 0.04 642 0.20 0.18 0.47 14.07 0.774 3.34 0.50 0.26 0.02 643 0.30 0.65 0.91 13.22 0.294 3.48 0.75 0.47 0.09 644 0.17 0.65 0.61 15.86 0.761 0.77 0.84 0.19 0.20 645 0.06 0.06 0.27 7.07 0.039 1.33 0.60 0.09 0.08 646 0.22 0.33 0.54 10.71 0.948 1.29 0.85 0.32 0.17 647 0.01 0.15 0.50 5.10 0.336 1.78 0.46 0.07 0.08 648 0.11 0.17 0.40 7.60 0.529 0.58 0.73 0.49 0.22 649 0.19 0.25 0.93 9.53 0.359 0.44 0.51 0.02 0.11 650 0.19 0.28 0.35 15.27 0.173 0.85 0.15 0.06 0.04 651 0.21 0.13 0.52 16.32 0.798 2.91 0.46 0.28 0.22 652 0.21 0.05 0.92 16.90 0.086 1.14 0.29 0.35 0.02 653 0.29 0.71 0.63 15.04 0.360 3.24 0.97 0.44 0.11 654 0.10 0.41 0.69 8.44 0.952 0.41 0.86 0.23 0.22 655 0.17 0.59 0.60 8.03 0.211 2.00 0.27 0.12 0.18 656 0.18 0.33 0.99 11.57 0.949 0.86 0.04 0.03 0.19 657 0.22 0.29 0.57 17.19 0.536 3.10 0.99 0.37 0.22 658 0.09 0.34 0.38 9.48 0.282 1.54 0.99 0.09 0.23 659 0.19 0.36 0.70 12.49 0.532 2.26 0.87 0.07 0.05 660 0.02 0.21 0.20 11.01 0.622 1.39 0.45 0.25 0.01 661 0.28 0.16 0.75 9.37 0.385 3.33 0.07 0.29 0.19 662 0.17 0.46 0.21 11.99 0.656 2.64 0.07 0.36 0.19 663 0.11 0.22 0.85 16.73 0.273 0.38 0.76 0.38 0.09 664 0.16 0.07 0.94 8.41 0.574 0.99 0.04 0.28 0.09 665 0.02 0.30 0.76 17.55 0.400 0.62 0.67 0.20 0.15 666 0.20 0.36 0.97 9.41 0.081 2.04 0.06 0.33 0.11 667 0.07 0.55 0.24 14.37 0.947 3.03 0.96 0.33 0.17 668 0.03 0.32 0.83 17.23 0.339 1.41 0.30 0.36 0.17 669 0.03 0.72 0.62 15.87 0.096 1.59 0.34 0.11 0.08 670 0.16 0.07 0.67 14.75 0.548 3.03 0.94 0.47 0.09 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 641 - 0.967 - - 0.82 4.30 0.78 642 - 0.431 - - 2.47 4.79 1.33 643 1.039 0.860 - - 1.92 1.56 0.81 644 1.958 1.934 - - 0.75 0.99 1.63 645 0.320 1.331 - - 0.57 4.70 0.76 646 0.776 1.709 - - 3.01 2.31 0.66 647 1.028 0.752 - - 2.48 2.63 1.00 648 1.708 1.127 - - 3.02 2.50 1.49 649 - - 1.216 - 1.42 1.11 0.95 650 - - 0.082 - 4.09 4.87 1.77 651 - - 0.652 - 0.62 0.97 1.84 652 - - 0.621 - 4.67 3.08 0.90 653 - - 1.640 - 1.01 0.75 0.43 654 - - 1.396 - 3.27 0.43 1.93 655 1.643 - 1.563 - 1.07 1.32 1.53 656 1.141 - 1.798 - 3.23 0.26 0.72 657 0.131 - 0.793 - 4.13 1.22 1.01 658 0.304 - 0.200 - 0.60 3.44 1.19 659 0.304 - 0.704 - 3.87 1.33 1.88 660 1.823 - 1.946 - 3.48 3.63 1.85 661 - 0.176 1.644 - 1.16 2.52 0.88 662 - 0.786 1.458 - 3.26 1.88 0.41 663 - 0.819 1.059 - 4.22 3.38 1.07 664 - 1.909 0.090 - 3.16 1.36 0.75 665 - 0.777 0.258 - 4.20 2.31 0.97 666 - 0.072 0.221 - 4.11 3.01 0.53 667 1.272 1.462 1.647 - 4.49 2.64 0.92 668 0.081 1.588 0.181 - 4.48 2.79 1.83 669 1.461 1.159 1.159 - 0.97 2.71 1.19 670 1.063 1.859 1.360 - 0.47 4.15 0.54 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 641 0.0015 0.005 0.013 6 172 20 642 0.0224 0.005 0.015 3 161 17 643 0.0162 0.008 0.006 1 139 22 644 0.0226 0.007 0.002 2 133 39 645 0.0067 0.006 0.011 2 171 19 646 0.0088 0.007 0.009 6 180 31 647 0.0089 0.009 0.003 7 139 22 648 0.0021 0.002 0.010 6 174 32 649 0.0132 0.002 0.006 0 165 18 650 0.0228 0.008 0.009 1 139 10 651 0.0107 0.004 0.014 7 173 11 652 0.0018 0.008 0.019 4 170 11 653 0.0213 0.008 0.020 4 158 18 654 0.0045 0.003 0.005 7 164 19 655 0.0212 0.001 0.009 4 167 35 656 0.0068 0.005 0.009 4 143 30 657 0.0010 0.004 0.013 0 147 13 658 0.0288 0.001 0.016 1 155 14 659 0.0259 0.009 0.017 5 170 13 660 0.0165 0.003 0.010 5 170 37 661 0.0118 0.009 0.004 6 133 28 662 0.0061 0.008 0.014 0 161 26 663 0.0245 0.001 0.009 0 132 21 664 0.0173 0.007 0.003 2 149 30 665 0.0243 0.005 0.014 4 140 20 666 0.0261 0.008 0.009 1 132 8 667 0.0022 0.009 0.013 7 154 48 668 0.0222 0.007 0.015 5 132 20 669 0.0074 0.010 0.002 4 145 45 670 0.0275 0.007 0.008 7 170 47 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 671 0.09 0.57 0.86 5.19 0.536 1.89 0.96 0.38 0.17 672 0.06 0.16 0.25 17.61 0.897 2.60 0.23 0.50 0.15 673 0.16 0.65 0.72 17.33 0.464 1.27 0.55 0.25 0.12 674 0.07 0.73 0.52 8.61 0.571 0.70 0.29 0.05 0.15 675 0.02 0.30 0.33 15.51 0.063 1.98 0.28 0.06 0.21 676 0.25 0.38 0.82 16.27 0.759 1.27 0.34 0.20 0.02 677 0.13 0.07 0.65 8.78 0.012 1.33 0.81 0.39 0.01 678 0.06 0.03 0.50 16.98 0.150 1.62 0.55 0.06 0.04 679 0.28 0.12 0.64 12.62 0.008 1.61 0.87 0.11 0.05 680 0.16 0.60 0.53 13.18 0.919 0.73 0.62 0.45 0.14 681 0.08 0.57 0.43 16.48 0.239 3.42 0.14 0.28 0.13 682 0.15 0.29 0.63 13.87 0.277 0.88 0.25 0.25 0.24 683 0.02 0.41 0.59 16.07 0.377 2.42 0.27 0.02 0.06 684 0.08 0.02 0.97 8.22 0.880 2.63 0.58 0.02 0.15 685 0.15 0.56 0.85 14.11 0.131 2.58 0.99 0.16 0.24 686 0.17 0.35 0.50 5.62 0.952 1.74 0.85 0.12 0.04 687 0.24 0.40 0.97 12.92 0.675 1.16 0.48 0.06 0.23 688 0.17 0.23 0.96 8.12 0.651 0.38 0.23 0.38 0.18 689 0.20 0.07 0.31 14.99 0.707 2.13 0.91 0.04 0.08 690 0.28 0.20 0.51 5.39 0.677 0.89 0.39 0.41 0.02 691 0.22 0.48 0.99 15.95 0.884 2.69 0.96 0.44 0.07 692 0.12 0.78 0.46 5.78 0.681 2.08 0.50 0.04 0.09 693 0.07 0.21 0.38 11.85 0.914 0.24 0.35 0.13 0.14 694 0.03 0.20 0.22 6.02 0.414 3.17 0.81 0.14 0.07 695 0.10 0.23 0.64 12.12 0.513 2.09 0.75 0.45 0.20 696 0.08 0.17 0.72 14.91 0.043 3.03 0.98 0.03 0.14 697 0.08 0.28 0.72 5.86 0.342 0.53 0.86 0.49 0.19 698 0.18 0.43 0.91 8.83 0.252 0.64 0.22 0.30 0.08 699 0.05 0.50 0.36 8.64 0.098 1.13 0.86 0.10 0.02 700 0.22 0.73 0.53 9.51 0.714 1.50 0.17 0.06 0.08 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 671 0.585 0.375 1.370 - 2.11 3.79 1.36 672 1.672 1.328 1.207 - 2.69 3.25 1.53 673 - - - 1.975 1.41 4.13 0.77 674 - - - 1.491 2.36 0.92 0.61 675 - - - 0.211 2.28 4.76 1.62 676 - - - 0.808 0.37 0.46 1.70 677 - - - 0.951 3.09 4.04 0.58 678 - - - 0.321 2.40 0.32 0.64 679 0.907 - - 0.578 4.75 2.92 1.60 680 1.795 - - 1.402 2.14 3.85 1.38 681 0.320 - - 0.487 3.42 4.74 1.46 682 1.134 - - 1.480 2.97 4.79 0.66 683 0.888 - - 1.045 2.37 0.76 1.37 684 1.317 - - 1.871 0.88 3.93 1.50 685 - 0.402 - 1.643 4.94 3.92 1.67 686 - 0.344 - 1.999 4.09 4.66 0.65 687 - 1.828 - 1.636 2.38 3.08 0.89 688 - 1.534 - 1.224 1.44 0.72 0.27 689 - 0.116 - 0.414 2.81 3.94 0.28 690 - 0.232 - 0.888 0.98 4.86 0.65 691 - - 0.816 1.329 4.74 2.62 1.96 692 - - 1.278 1.395 3.65 1.26 1.24 693 - - 0.685 1.771 4.21 2.40 1.79 694 - - 1.689 1.116 3.20 2.85 1.50 695 - - 0.985 0.118 2.21 4.22 0.99 696 - - 1.222 1.416 0.44 0.87 1.75 697 - 1.047 0.086 1.724 4.36 4.11 0.80 698 - 1.789 1.247 1.695 1.16 1.09 0.54 699 - 1.128 1.370 1.991 4.41 3.02 0.67 700 - 1.750 0.152 1.312 3.81 1.97 0.90 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 671 0.0028 0.005 0.011 3 135 31 672 0.0178 0.008 0.009 6 168 43 673 0.0078 0.001 0.017 6 146 29 674 0.0281 0.005 0.013 0 173 17 675 0.0285 0.004 0.013 4 175 15 676 0.0042 0.006 0.014 2 156 19 677 0.0250 0.001 0.013 1 144 15 678 0.0261 0.001 0.015 6 141 7 679 0.0179 0.004 0.019 6 175 21 680 0.0253 0.010 0.010 6 148 32 681 0.0135 0.006 0.016 5 139 11 682 0.0221 0.001 0.004 3 150 26 683 0.0017 0.003 0.018 5 158 22 684 0.0220 0.005 0.008 6 168 33 685 0.0186 0.006 0.009 5 156 22 686 0.0158 0.009 0.007 5 150 23 687 0.0245 0.008 0.001 1 152 38 688 0.0244 0.002 0.006 2 141 31 689 0.0252 0.006 0.009 4 169 16 690 0.0077 0.002 0.017 2 165 21 691 0.0262 0.006 0.007 5 155 28 692 0.0165 0.008 0.015 6 167 26 693 0.0184 0.001 0.008 6 155 29 694 0.0120 0.007 0.013 1 170 27 695 0.0221 0.002 0.007 7 167 16 696 0.0291 0.002 0.006 2 146 27 697 0.0281 0.010 0.016 6 137 35 698 0.0141 0.002 0.015 4 167 48 699 0.0269 0.004 0.010 6 163 39 700 0.0172 0.006 0.017 5 154 37 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone STEEL OF INVENTION (Mass.%) No. C Si Mn Cr Mo W V Nb N 701 0.21 0.24 0.91 9.56 0.450 2.84 0.43 0.35 0.10 702 0.11 0.45 0.54 6.45 0.127 2.97 0.52 0.39 0.17 703 0.04 0.06 0.91 17.65 0.088 2.98 0.27 0.11 0.12 704 0.07 0.50 0.68 15.12 0.175 2.36 0.99 0.40 0.15 705 0.02 0.09 0.92 9.65 0.220 0.56 0.55 0.45 0.11 706 0.28 0.26 0.70 5.48 0.547 1.95 0.26 0.42 0.08 707 0.08 0.10 0.29 13.64 0.508 2.73 0.47 0.23 0.13 708 0.08 0.26 0.36 6.01 0.935 2.36 1.00 0.30 0.24 709 0.25 0.61 0.78 6.28 0.160 0.27 0.21 0.29 0.23 710 0.25 0.25 0.61 6.03 0.523 0.90 0.42 0.13 0.19 711 0.02 0.23 0.93 9.59 0.862 2.06 0.48 0.23 0.08 712 0.26 0.79 0.39 8.10 0.500 1.49 0.20 0.50 0.09 713 0.03 0.64 0.88 12.65 0.286 2.04 0.92 0.38 0.08 714 0.01 0.05 0.66 8.10 0.055 3.13 0.02 0.27 0.13 715 0.02 0.05 0.39 5.22 0.632 0.88 0.28 0.10 0.18 716 0.30 0.53 0.76 8.47 0.369 3.08 0.07 0.02 0.08 717 0.07 0.17 0.42 9.12 0.586 0.88 0.70 0.21 0.16 718 0.30 0.03 0.45 11.69 0.139 2.02 0.04 0.34 0.02 719 0.22 0.37 0.31 13.79 0.332 0.94 0.87 0.08 0.20 720 0.07 0.65 0.66 13.50 0.034 2.15 0.11 0.09 0.09 STEEL OF INVENTION (Mass.%) No. Ti Zr Ta Hf Co Ni Cu 701 - 1.320 1.239 1.310 3.31 1.89 1.83 702 - 1.487 0.298 1.641 2.09 2.01 0.47 703 1.220 - 0.025 1.004 4.23 3.95 1.02 704 1.510 - 0.055 0.054 1.70 4.49 1.37 705 1.549 - 1.089 1.455 0.90 0.46 0.35 706 1.018 - 0.804 0.923 1.13 0.73 1.26 707 1.560 - 1.858 0.093 1.51 2.03 1.99 708 0.886 - 1.929 0.641 3.71 3.61 0.46 709 0.631 1.371 - 1.234 2.11 2.30 1.77 710 1.504 0.654 - 0.556 0.72 4.48 1.13 711 1.160 0.598 - 0.273 3.54 4.56 0.92 712 1.235 1.864 - 1.048 0.22 1.76 1.77 713 1.457 1.158 - 1.581 4.39 4.95 1.59 714 0.470 0.131 - 1.527 0.82 1.28 0.97 715 0.946 0.427 0.199 0.537 0.68 4.31 1.40 716 0.571 0.776 0.577 1.322 0.90 1.37 0.81 717 1.005 1.793 1.990 0.532 3.01 3.62 0.71 718 0.923 1.196 1.157 1.843 1.45 0.69 1.69 719 0.972 1.619 0.713 1.907 2.57 3.69 0.72 720 1.877 1.728 0.321 1.400 0.80 4.72 0.25 STEEL OF INVENTION (Mass.%) No. P S O D-CRS HAZCRS M% 701 0.0096 0.010 0.003 6 166 39 702 0.0291 0.010 0.004 3 179 32 703 0.0261 0.009 0.007 2 169 31 704 0.0253 0.006 0.009 5 164 21 705 0.0221 0.005 0.007 5 167 40 706 0.0117 0.002 0.017 3 131 34 707 0.0040 0.007 0.007 6 134 41 708 0.0088 0.008 0.003 5 152 35 709 0.0064 0.004 0.010 6 165 38 710 0.0220 0.007 0.008 4 149 32 711 0.0205 0.002 0.001 3 133 26 712 0.0270 0.001 0.016 4 144 36 713 0.0220 0.003 0.012 6 159 42 714 0.0151 0.002 0.013 4 158 29 715 0.0162 0.004 0.017 5 166 29 716 0.0208 0.009 0.002 7 138 30 717 0.0240 0.007 0.002 2 176 52 718 0.0208 0.008 0.006 2 157 46 719 0.0206 0.004 0.018 0 159 46 720 0.0044 0.009 0.017 2 161 52 D-CRS: Difference between the creep rupture strength at 600°C for 100.000 hours estimated by linear extrapolation of a base steel and that of a weld heat-affected zone (MPa) HAZCRS: Creep rupture strength of a weld zone at 600°C for 100.000 hours estimated by linear extrapolation (MPa) M%: Value of (Ti% + Zr% + Ta% + Hf%) in M of M 23 C 6 type carbides in a weld heat-affected zone POSSIBILITY OF UTILIZATION IN THE INDUSTRY As described above in detail, the present invention provides a martensitic heat-resisting steel excellent in HAZ-softening resistance and exhibiting a high creep strength at high temperature of at least 550°C. The present invention can, therefore, provide materials at low cost which can withstand operation conditions at high temperature and high pressure in thermal power plant boilers, etc. Accordingly, the present invention extremely contributes to the development of the industry.

Claims: A martensitic heat-resisting steel excellent in HAZ-softening resistance comprising, in terms of % by mass, 0.01 to 0.30% of C, 0.02 to 0.80% of Si, 0.20 to 1.00% of Mn, 5.00 to 18.00% of Cr, 0.005 to 1.00% of Mo, 0.20 to 3.50% of W, 0.02 to 1.00% of V, 0.01 to 0.50% of Nb, 0.01 to 0.25% of N, up to 0.030% of P, up to 0.010% of S, up to 0.020% of O, at least one element selected from the group consisting of Ti, Zr, Ta and Hf in an amount of 0.005 to 2.0% for each of the elements, optionally at least one element selected from the group consisting of Co, Ni and Cu in an amount of 0.1 to 5.0% for Co or Ni, and 0.1 to 2.0% for Cu and the balance Fe and unavoidable impurities, the value of (Ti% + Zr% + Ta% + Hf%) in the metal component M of M 23 C 6 type carbides precipitated in the tempered martensite structure of the steel being from 5 to 65%. The martensitic heat-resisting steel according to claim 1, wherein said steel comprises, in terms of % by mass, at least one element selected from the group consisting of Co, Ni and Cu in an amount of 0.1 to 5.0% for Co or Ni, and 0.1 to 2.0% for Cu. A process for producing a martensitic heat-resisting steel excellent in HAZ-softening resistance, comprising the steps of adding at least one element selected from the group consisting of Ti, Zr, Ta and Hf in an amount of 0.005 to 2.0% for each of the elements, in terms of % by mass, to a molten steel comprising 0.01 to 0.30% of C, 0.02 to 0.80% of Si, 0.20 to 1.00% of Mn, 5.00 to 18.00% of Cr, 0.005 to 1.00% of Mo, 0.20 to 3.50% of W, 0.02 to 1.00% of V, 0.01 to 0.50% of Nb, 0.01 to 0.25% of N, up to 0.030% of P, up to 0.010% of S, up to 0.020% of O, optionally at least one element selected from the group consisting of Co, Ni and Cu in an amount of 0.1 to 5.0% for Co or Ni, and 0.1 to 2.0% for Cu and the balance Fe and unavoidable impurities, during the period from 10 minutes before completion of refining to completion of refining, casting said molten steel, hot working the resulting casting, solution treating the hot worked product thus obtained, subjecting said hot worked product having been solution treated to cooling stop at a temperature from 950 to 1,000°C in the course of cooling said hot worked product from the solution treating temperature to room temperature, holding said hot worked product at the temperature for 5 to 60 minutes, and tempering said worked product. The process for producing a martensitic heat-resisting steel according to claim 3, wherein said molten steel comprises, in terms of % by mass, at least one element selected from the group consisting of Co, Ni and Cu in an amount of 0.1 to 5.0% for Co or Ni, and 0.1 to 2.0% for Cu. The process for producing a martensitic heat-resisting steel according to claim 3, wherein said hot working is rolling for producing a plate product and a tube product. The process for producing a martensitic heat-resisting steel according to claim 3, wherein said hot working is forging.

Inventors: FUJITA TOSHIO, HASEGAWA YASUSHI, MIZUHASHI NOBUO, NAOI HISASHI, OHGAMI MASAHIRO, FUJITA, TOSHIO, HASEGAWA, YASUSHI, MIZUHASHI, NOBUO, NAOI, HISASHI, OHGAMI, MASAHIRO, HASEGAWA, YASUSHI NIPPON STEEL CORPORATION, MIZUHASHI, NOBUO NIPPON STEEL CORPORATION, NAOI, HISASHI NIPPON STEEL CORPORATION, OHGAMI, MASAHIRO NIPPON STEEL CORPORATION
Applicants: FUJITA TOSHIO, NIPPON STEEL CORP, FUJITA, TOSHIO, NIPPON STEEL CORPORATION
Application year: 1994
Main classification: C22C38
IPC codes: C21D8, C22C38, C21D6